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4a608bcf5d54cdcs972_manual.

1. 45 M Maintenance regular ccccceeeeeees 78 98 WIM IMIS 6 a aisha a aA 31 103 Mode FO serea e i 20 21 ModE SIR Gace te sect ice 20 21 Multi channel DSD to DSD 000 25 Multi channel DSD to PCM 22 39 41 Multi channel master cceeeeeeeeeeeeeees 68 Multi channel PCM to DSD 000000 44 50 Multi channel synchronisation 10 68 N Noise Shaping 060 29 33 71 91 93 Noise shaping NOISE POWET ccceceeee 91 O ODUONS arns ati atacain S 96 OULU MOGG aici 158 tee et adie nian edhe 28 Output Word Length cccceceeeeeeeeeeeeeees 29 Owner registration transfer c cc08e 113 dCS 972 User Manual dCs Ltd P Pans MOVING arenai e 98 Pans SMOL NG aiaia a a aS 98 Parts user serviceable ceceeee 98 101 POM TO DS Dosc 44 50 PNaASGaecan e eee 32 PL OCK ININE irasi aa a ae 63 PEE UN MA TANGE erin a 63 S Sample aliQnMent ccccsesceesseeseseeeeenees 64 Sample alignment AES3 in to out 66 Sample alignment AES3 to Word Clock 64 Sample rate conversion mode 20 21 Sample rate input 21 25 26 27 68 Sample rate output e 26 51 104 SDIF 2 Me SSaGG wise seilneet nt chest 76 Ee So N E eo eR a 37 SEMIEN 100 Setups recalling cccceeccsseeecseeeeeeeseeeess 44 Setups STOriNg
2. 100 00 120 00 140 00 160 00 180 00 Manual for Software Version 2 3x January 2001 Spot Q Noise for DSD Filters in 400 Hz bandwidth F1 F2 F3 F4 F5 F6 F7 a 120dB in 20 kHz 10 100 1000 Frequency kHz Figure 30 DSD output spot Q Noise for the various Filter options Integrated Q Noise for DSD Filters normalised for Full Scale DSD at 0dB FI a F3 a F5 F6 F7 KF y 10 100 1000 Frequency kHz Figure 31 DSD Output integrated Q Noise for the various Filter options dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Spot Q Noise for DSD Filters F Weighted in 400 Hz bandwidth 80 20 F1 sa a a eles F2 120 B 20 i F4 o 140 i e 40 a SS A 160 CZ re 60 F E iy F7 D 2 180 E Pe 80 2 o ee aa pom F weighting curve D z right hand scale g o 200 100 2 O Z O 220 120 240 140 260 160 280 180 0 1 1 10 100 1000 Frequency kHz Figure 32 DSD Output F weighted Q Noise for the various Filter options DSD Format showing Full Scale Signal dCS 972 SW v1 54 1 5 1 0 5 0 0 5 1 1 5 0 50 100 150 200 250 300 350 400 450 Time usecs Figure 33 DSD showing 0 dBO full scale DSD has only two levels printer artefacts make it look like more 500 dCS 972 User Manual dCS Ltd Zoomed Passband Response dB Zoomed
3. dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Output audio bandwidth is poor e During sample rate conversion the signal is digitally filtered this is essential for good performance The output audio bandwidth will usually be slightly less than half the lowest sample frequency involved in the conversion A stereo output signal is expected but signal is present on one channel only e Check that Balance is not set to one side e If SDIF 2 is used check that Ch1 and Ch2 are both connected e Check you are not using a Dual AES mode with just one cable connected A stereo output signal is expected but one channel of the input appears on both channels of the output e Check that the receiving unit expects two wire AES or SPDIF mode rather than double speed Tone appears on the outputs e Press the Status button and check that the IMANU label is NOT visible If it is select Test Mode and set the Test Generator to Off e Low level idle tones sometimes appear on the outputs if the signal on the input drops to a level below the output word length and Noise Shaping is on with no Dither This may arise during editing sessions for example where digital silence is coming in to the unit but the Detect Silence function is off This situation will usually not arise if an unedited input from an ADC is being used although even in these circumstances enough noise shaping must be used Consider using either
4. All noise modulation and unpleasant effects removed but noise floor is high All noise modulation and unpleasant effects removed Not much perceived noise penalty Okay with input noise floors down to 102 dB Unconditionally free from truncation effects with all inputs Okay with input noise floors down to 120 dB Unconditionally free from truncation effects with all inputs Table 11 Dither and Noise Shaping Noise Powers even at full scale It is just that it is in a part of the spectrum the ear cannot hear 32 16 bit Q noise is 98 1 dB relative to a full scale sine wave DSD carries this further The principle is the same but with DSD there is more noise than there is signal dCS 972 User Manual dCS Ltd Manual for Software Version 2 3x January 2001 Noise shaping on its own is not perfect It relies on a small amount of noise in the input signal to generate the frequency shaped correction signal and if there is very low noise in the input signal this mechanism can break down In reality such a situation can only occur with test signals digitally generated signals or silences introduced in editing If one of these situations may arise any chance of a problem can be completely removed by adding a dither signal as well as using noise shaping The noise shaping shapes the dither in the dCS 972 architecture If Noise Shaped Triangular dither is used then there is very little weighted degrada
5. Se 7 AEs aimee a Si la gah i e a ae L a 127 2 00 wdi pos 4 000 10 00 1 Ms de 2 5000 us O 000 g 2 J000 Us J00 ns div repetitive Trigger Mode Edge E f 2 496 Figure 20 AES3 in to AES3 out 44 1 kS s dCS 972 User Manual dCS Ltd Manual for Software Version 2 3x January 2001 DSD data out is aligned to Word Clock transitions as below the word clock edges align with the data transitions rather than in the middle of the data eye If you need them the other way round use an additional 10m of cable in the Word Clock Out path fo running 1 2 90 diw BA lim 2 500 1 000 1 30s de 2 2 00 Vrdi pos 2 000 1 000 7 30s de 1 0000 us O 000 g 1 0000 us 200 ns div repetitive Trigger Mode Edge 2 f 2 250 Figure 21 DSD data and Word Clock out dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Multiple Channel Sync ing Multiple channel sync ing requires more things to be in sync than two channel work the PLL must not be dual modulus the DSP algorithm must load with a constant group delay and the frame and block syncs must agree The dCS 972 meets all these constraints with the addition of a syncing signal transmitted from a master unit to subsequent slave units To do this it passes information in the User Bits of the AES3 message To slave adequately units must have this sync information input to the AES CLK Input via a sync link Each slave wil
6. The meters can be used to monitor DSD by setting a DSD to PCM conversion and using the appropriate output data rate Watch Out for this One If the unit is tested with sine waves at frequencies which divide almost exactly into the sampling frequency e g 6 001kKHz signal 48 kS s sampling frequency the segments on the right hand side of the meter will flicker This effect disappears if the signal frequency is changed by about 10Hz and so it is not a problem when monitoring music It is caused by the signal beating with the sampling frequency dCS 972 User Manual dCS Ltd Manual for Software Version 2 3x January 2001 Display Submenu OOPS The final option on the top level menu is Display Select this and press gt Berigdht a Contrast m Cursor Clockwise Down Backlight off after 1 min Bright adjusts the brightness of the display backlight and Contrast adjusts the LCD display contrast These should be set for optimum readability The length of the solid bars indicate the setting of each parameter there are 27 levels for each To adjust the brightness select Bright and press Set The cursor will change to the symbol Set the required brightness with the rotary control then press Set again to exit adjustment mode The Contrast is adjusted in a similar manner It is possible to turn the contrast to such a low setting that it is very difficult to read the display If this happens and the menu lev
7. Multi channel Sample Rate Conversion with bit aligned source If the source data is bit aligned for example from a multitrack recorder up to four or five dCS 972 s may be set to operate synchronously using the sync link connections shown above from one unit s AES CLK Output to the next unit s AES CLK Input For all units set the Multi channel Sync option to On The top unit will set up as a master the other ones will set up as slaves Make sure that all the other settings are the same on each unit See section Multiple Channel Sync ing page 68 for how aligned is bit aligned These are set up for PCM in to DSD out in Store 1 and for PCM in to 96 kS s out in Store 12 by dCS You can overwrite them dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Multi channel Sample Rate Conversion Using a Master Clock TO RECORDER 44 1kS s WORDCLOCK dCS 992 Master Clock 96kS s Chl amp 2 ote Ee MAINS FUSE 2A T ON OFF 96kS s Ch3 amp 4 AES1 yo AES CLK CH1 CH2 ckK g S 44 1kS s CA f SOURCE O 7 96kS s Ch5 amp 6 MAINS FUSE 2A T ON OFF 96kS s Ch7 amp 8 Figure 10 Multi channel Sample Rate Conversion with Master Clock You can use a dCS 992 Master Clock to sync up the source and be the master The sync link cabling starts from the master clock cable A an
8. tnt Besvs Ot 44 1 bk 5s Waveform Generator Sine AMelitude 18 6dB Fresuency 1 seek Hz in DSD mode it is a PCM generator operating at a sample rate of 705 6 kS s and then converted to DSD This means that the maximum frequency that it can give out is 352 8 KHz dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 To set up the generator press twice to move to the menu screen then display the Test menu BGenerator Sine Generator AmeLlitiude 15 dE Generator Freswency H S999kHz Self Test The Generator options are Off Sine and Square Press Set to scroll through these IMPORTANT The initial Generator Amplitude is 18dB0 If the dCS 972 is ultimately driving speakers or headphones ensure the system gain is at a reasonable setting before turning the generator on Generator Amplitude Adjustment Select Generator Amplitude and press Set to adjust it Turn the rotary control counter clockwise to reduce the amplitude in 0 5dB steps or clockwise to increase it Attempting to increase the amplitude above OdB causes the setting to wrap around to 120dB When the required amplitude is displayed press Set again to update the setting Generator Frequency Adjustment Select Generator Frequency and press Set to adjust it The following screen appears I 1 ama l Freauencys A a The frequency resolution of the generator is about 1 part in 2 of the sample rate about 10uHz at 48
9. Non Audio On Off Mode Source Destination Professional On Off Non Audio On Off Copy Permit On Off Format January 2001 AES1 AES2 Dual AES SPDIF1 RCA SPDIF2 BNC SPDIF3 Toslink PCM SDIF 2 DSD SDIF 2 192 kS s 176 4 kS s 96 kS s 88 2 kS s 48 kS s 44 1 kS s 32 kS s 24 kS s 22 05 kS s 16 kS s 12 kS s 11 025 kS s Auto Normal Dual AES DSD SDIF 2 DSD SDIF 3 24 bits 23 bits 8 bits Off Top Hat Triangular Noise Shaped Triangular Not Indicated Two Channel Single Channel Primary Secondary Stereophonic Source Byte 1 Source Byte 2 Source Byte 3 Source Byte 4 Destination Byte 2 Destination Byte 3 Destination Byte 4 2 Ch Gen Format Compact Disc 2 Ch Enc Decode DAT dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Gain adjust Gain Balance Balance adjust Reset max hold Maximise Display max hold Maximise Normal Swap Channels See Normal Left inverted Phase On Off De emphasis 50 15 usec add or remove De emphasis CCITT J17 Emphasis 50 15 usec Emphasis CCITT J17 Right inverted Both inverted De Pre emphasis Input Sync Source Output Mode Word Length Noise Shaping Dither CRC Errors Right Parity Errors Left Parity Errors Right Invalid Errors Left Invalid Errors Right Hold Unhold Reset Display Customise Error Monitor All Errors Generator Lesh Off Sine Square
10. SDIF 2 or Dual AES at 88 2k 96k 176 4k or 192kS s AES1 AES2 eee gt B x CH1 CH2 CLK AES EBU Outputs MAINS FUSE 2A T ON OFF SPDIF2 SPDIF3 SYNC IN CH1 CH2 CLK Se i ei SDIF 2 Output DSD out Figure 7 PCM to DSD conversion The dCS 972 converts PCM to DSD including 176 4 kS s to DSD using the arrangement given below Connect any digital audio source of any Word Length between 8 and 24 bits using single or dual wire AES to the AES inputs or using single or double speed SDIF 2 to the SDIF 2 inputs or using single wire SPDIF to the appropriate SPDIF input and select input accordingly Set Output Mode to DSD Choose a filter if you wish Output via the SDIF 2 connectors two data cables and one word clock Sample Rate Conversion settings The settings are preloaded in store 10 by dCS although they may be overwritten Sample Rate Conversion On Audio Input Select Any even including Dual AES if the Input Frequency is any of 192 kS s 176 4 kS s 96 kS s or 88 2 kS s sync Source Any Input Frequency Any Output Frequency n a Output Mode DSD Filter Any Output Wordlength n a Noise Shaping n a Dither n a Detect Silence n a dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Using a Master Clock AES EBU Ou SPDIF1 SPDIF2 SPDIF3 SYNC IN we 7N 22 6 ec eln o Out DIGITAL OUT AES REF
11. cceccceeeeseeeeeeeeeeeeeees 28 Table 4 DSD Filter SUMMALY cccccccsececeececeeeeceeeeceeeceeeseueeseueesseeeseeeseas 58 Table 5 DSD Filter Performances anren nina aaa aa Aai 59 Table 6 Typical Spurious Level vs Conversion ccccecceseceeeeeeeeeeeeeeeeaeeeens 61 Table 7 Group Delays PCM to PCM transitions ccceecceeceeeeeeeeeeeeeeeeees 62 Table 8 Noise Shape Orders by Output Sample Rate cccecceeeeseeeeee es 71 Table 9 Noise Added by Dither Types cccccccccceeeeseeeeeeeeseeeeeseeeeseeeseeeens 72 Table 10 SDIF 2 Message Table cccccccseccceeeeceeeeceeecceeeceuseceueesaeeenseeseas 76 Table 11 Dither and Noise Shaping Noise POWe S ccccesceceeeeeeeeeeeeeees 91 Table 12 Options available iscsi icech tcaetectc eee hans deena esas teens idennieeneeaeets 96 Table 13 dCS Phone Numbers cccccececececcccccececececececcacaceceneneneauaeenenenes 105 dCS 972 User Manual dCS Ltd Figures Manual for Software Version 2 3x January 2001 PIQUE 1 Rear PAN Choice tetas vuceenas bated a ansehen lovanetand ented A 10 Figure 2 Front Panel asirica aaa aa a a a a a a a 14 Figure 3 Double Speed 24 96 to CD format nannnnennnnnneneneerrnennreneneesnrenenne 46 Figure 4 Converting dual AES 24 96 to a single wire double speed one 47 Figure 5 Upsampling a CD to 24 96 or 24 192 ccceccecseeeee
12. 96 kS s due to limitations in the Toslink devices In practice the interface has been shown to operate correctly with other dCS equipment at all 10 sample rates but dCS cannot guarantee this due to Toslink manufacturing variations dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Message Handling The dCS 972 strips the message information from the incoming data The message in the outgoing data is set using the AES Message Edit and SPDIF Message Edit menus located under the Sample Rate Conversion menu AES EBU Message Handling The AES3 1992 standard was written at a time when only 3 sample rates were in common use in the audio industry dCS started manufacture of ADCs featuring 96 and 88 2 kS s sample rates in 1993 and we have evolved modifications to AES3 1992 which accommodate these innovations These are currently being considered by the AES The AES EBU interface transmits a data structure that conforms to the dCs version of AES3 1992 This contains 28 bits of Manchester encoded data and a 4 bit near Manchester encoded preamble in a subframe and subframes are further assembled in a block and frame structure Each subframe contains e preambles to allow the receiver to sync up e up to 24 bits of audio data transmitted Isb first e V a validity bit e U a user bit for the User Message e C a Channel Status bit for the System Message e P a parity bit IMPORTANT The AES EBU interface and th
13. AES A amp B outputs There is no information added in the process although you may wish to check theory here Connect a source of CD material to the SPDIF 1 input on the dCS 972 Load the setup from Store 3 or use the settings below Output Dual AES data from both AES A and AES B to a DAC of your choice dCS Elgar dCS Delius or dCS 954 Sample Rate Conversion settings The settings below are preloaded into Store 3 by dCS although they may be overwritten Sample Rate Conversion On Audio Input Select SPDIF 1 Sync Source Audio Input Input Frequency Auto 44 1 kS s Output Frequency 96 kS s Output Mode Dual AES Filter Filter 2 Output Wordlength 24 Noise Shaping Off Dither Off Detect Silence Off AES Message Edit SPDIF Message Edit Professional On Non Audio Off Mode Stereophonic Professional On Non Audio Off Copy Permit On Format 2 Ch Gen Format dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 General Sample Rate Conversion and Distribution From ANY format AES SPDIF Toslink SDIF 2 at any sample rate 11 025k 12k 16k 22 05k 24k 32k 44 1k 48k 88 2k or 96kS s or Dual AES at 88 2k 96k 176 4k or 192kS s ee Ae 2 A AES1 AES2 AES CLK In oleje g le oO CH1 CH2 CLK g 3 AES EBU Outputs To ALL formats AES SPDIF Toslink SDIF 2 at any sample rate 11 025k 12k 16k 22 05k 24k 32k 44
14. EBU interface and the SPDIF interface have similar data structures although the messages are completely different The two structures are identified in the data domain by the use of the Consumer Professional bit bit I in the message A I indicates AES EBU format a 0 indicates SPDIF format The default SPDIF message attached to the output data by the unit before being changed by the user is as follows Professional Off Non Audio Off Copy Permit On Format 2 Channel General Format See EN 60958 1995 or IEC 958 1989 with amendments 1 amp 2 The structure of the message is sufficiently complex that it is best to read the source material dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 SDIF 2 Message Handling The SDIF 2 interface is a 4 wire NRZ interface so the DC level on each signal line may not be constant It contains 20 bits of audio data and has a block structure of 256 stereo samples rather than the 192 of AES EBU There are 8 bits of message per channel per sample with a further 3 bits being used for an illegal code based sync code Of the 8 bits per sample the 8 in the first sample are reserved for system messaging and the rest are for User messages The 4 wires are Ground return Left Channel Right Channel Word Clock The sync codes enable data recovery without the word clock if necessary but with the number of data formats in current operation this method of locking is st
15. Generator Amplitude Generator Frequency Self Test Info Normal Bit Activity Faster Monitor None 320 ms 640 ms 960 ms Decay Time Fastest Instant Level Meters Peak Hold 1280 ms 1600 ms Bar Infinite Brightness Display Contrast Cursor 1 mins Backlight off after aa Table 1 Menu Tree dCS 972 User Manual dCS Ltd Top Menu Manual for Software Version 2 3x January 2001 The top menu contains the major entries Sample Rate Conversion Format Conversion Error Monitoring Test Info Bit Activity Monitors Level Meters and Display as follows ate Lonvers1ioan ets Convers ion Error Monitor Bit Activity Monitor Level Meters Disrelsay In many cases the settings in one menu do not affect those in others In other cases they do and where this occurs the menu will automatically adjust to allow only valid options The unit can operate in one of two main modes Sample Rate Converter SRC mode and Format Converter FC mode In SRC mode the unit performs DSP on the signal and gain is always reduced by 0 01dB This is because many of the other operations such as dithering or noise shaping add a small amplitude signal so we reduce the amplitude a small amount to prevent spurious Clips It also means that for simple operations such as Dual AES in to double speed AES out bits in will not be the same as bits out Because in some cases this is important the unit can also oper
16. Initial Warranty Extended Warranty Warranty Exclusions Obtaining Service Manual for Software Version 2 3x January 2001 dCS Ltd warrant this product against defects in materials and workmanship for a period of 90 days from receipt by the end user Warranty repairs must only be carried out by dCS or an authorised dCs Distributor The period of the Warranty cover may be extended to 1 year from receipt by the end user at no extra cost by registering your purchase with dCS Your Reseller should have arranged this on your behalf by filling in an Owner Registration form at the time of sale and returning it to dCS If you do not receive an Extended Warranty Certificate for this unit within 30 days of purchase please note the serial number on the underside of the unit and contact dCs Registration ensures you will receive information on important hardware and software upgrades as they become available If you sell the unit within the first year the balance of the Extended Warranty may be transferred to the new owner by completing the Owner Registration Transfer form page 113 and returning it with the Extended Warranty Certificate to dCs The Warranty on this dCS 972 shall be void if e the product is misused in any way e any unauthorised modifications or repairs are carried out e the product is not used in accordance with the Operating Conditions stated on page 78 of this manual e the product is serviced or repaired except b
17. Ltd Amplitude dB Amplitude Real Data dB 100 120 140 fs 160 100 120 140 160 January 2001 Spectra of 90dB 24 bit sinewave truncated to 16 bits with dither options dCS 972 SW v1 54 24 bit source data TEREPE 16 bit truncation no dither 16 bit truncation Top Hat dither 16 bit truncation Triangular dither 16 bit truncation Noise Shaped Triangular dither oh rah AA de a mw ha Aah Anh Naa ie 4 6 8 10 12 1 Frequency kHz 16 18 20 22 Figure 28 Truncated small signal FFT with and without dither Noise Shaper and Noise Shaper with Dither Performance dCS 972 SW v1 54 TETTE 16 bit truncation 10th order noise shaping no dither 16 bit truncation 10th order noise shaping Top Hat dither 16 bit truncation 10th order noise shaping Triangular dither a APR Se BF 16 bit truncation 10th order noise shaping Noise Shaped Triangular dither e T POT ga as cal fF n pt nwt Pal I hte ie le Vd i Le To gt r WO Amar Aw ry a is m as SOT ae T Fi ee 2 aad Fi 5N Ta Fi 1 ae si oe we Cj Ue ee gn ae p At ai bii 4 6 8 10 12 14 16 18 20 22 Frequency kHz Figure 29 Truncated small signal FFT showing noise shaping with and without dither dCS 972 User Manual dCS Ltd Q Noise rel Full Scale DSD dB Integrated Q Noise Power dB 100 120 140 160 180 200 20 00 20 00 40 00 60 00 80 00
18. SDIF 2 Message Handling 76 SDIF 3 Message Handling 76 Power Consumption 77 Size Weight and Operating Conditions 78 dCS 972 Performance Curves acai sac hacesinecievssaceaiies sve siccaacaeacwsbuatiosaswenncessaneee 80 General Technical Information cccccscceeeeeeeeeeeeeeeeeeneeeneseneneneeenesenesenesens 90 Word Length Reduction 90 OUI S iura EER 96 Locking to Video Sample Rates 96 Mains Supply Voltage 96 Ordering Options for a New Unit 96 Having Your Options Changed 96 Maintenance and Suppolt cccccccceeeeeeeeeeeeeeeceneeeneceneeensceesceeseneeeeeeseesenesens 98 Hardware 98 Service amp Maintenance 98 User Changeable Parts 98 Software 99 Installing New Software 99 dCS 972 User Manual dCs Ltd Tables Manual for Software Version 2 3x January 2001 Warranty 100 Initial Warranty 100 Extended Warranty 100 Warranty Exclusions 100 Obtaining Service 100 Update or Calibration 101 Safety and Electrical Safety 101 PFOUDICSNOOUNG risiano Ea 102 FAQs 102 If You Need More Help 105 Other Information 105 Indexes and Software Version Numbers ccccscceeeeeeeeeeeeeeeeeeeeeeneeeneeenes 106 Definitions of Units 106 Full Contents 107 Tables 109 Figures 110 Keywords and Phrases 111 Owner Registration Transfer 113 Table t Menu TeC aaa a a a aa 19 Table 2 One Pass and Two Pass Conversions 0ccceeeeeeeeeeeeeeeeeeeeeeeeeeeees 26 Table 3 Conversions with Multiple Filter Options
19. SS GT The bar consists of 27 segments each representing 1dB The dashed segments at the right of each bar are the Peak Hold indicators The indicator on the lower of the two bars shows that overloads full scale signals have occurred in the last monitoring period on that channel it says Over if you peer closely The decay of the overload is controlled by the Peak Hold function in the Level Meters menu below Numerical metering to a resolution of 0 1dB can be set up instead for example for accurate alignment in comparisons See Meter Type below to do this the display will change to In de uses Oat 44 1 kb 5 s OLO da 3 OL 2 2 2 because the dCS 972 reduces the signal level by 0 01dB this can only occur if gain is applied or if the unit is in Format Conversion mode and the input signal goes to full scale dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Meter Type Bar or Numerical To change between Numerical or Bar level metering or to change the meter characteristics return to the Level Meters menu and press to display the options Bieter Tyre Bars Decay Time Select Decay and press Set to display the Decay time options Level Meters Decay BHorrmal Faster Fastest Instant These options give the following characteristics Normal the bar length decays away at 32 ms segment Faster the bar length decays away at 16 ms segment Fastest the bar length dec
20. Specifications available from Philips System Standards and Licensing Licensing Support Building SFF 8 PO Box 80002 5600 JB Eindhoven The Netherlands dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 PCM input and or Output Performance Filtering The normal filtering considerations of passband ripple cutoff frequency and rate out of band stop band suppression and transient phase response apply to sample rate converters The dCS 972 uses linear phase FIR filters to avoid the limit cycle problems that come with many IIR filters Linear phase gives filters a symmetrical transient response before and after a transient pre ringing and post ringing The passband may or may not have a ripple depending on the conversion and or filter being used Cutoff frequency is gt 40 of the lowest sampling rate used in the conversion input or output The stop band is typically below 110 dB but varies with conversion and can be as low as 130 dB The frequency responses of two commonly used conversions 96 kS s to 44 1 kS s and 48kS s to 44 1 kS s are shown in Figure 35 and Figure 34 on page 85 The transient responses of the filters in the 96 kS s to 44 1 kS s conversion are shown below fe stopped 1 2 00 Vedi pos 2 000 10 00 1 Ms de m 2 00 Vedi mi 2 00 W div ms 2 00 Wediv 650 00 us 150 00 us 250 00 us 479 EP 100 usdi repetitive Trigger Mode current minim
21. Store 3 Upsampling preloaded with 44 1 kS s in Dual 96 kS s out You can overwrite this setup Store 10 Preloaded with PCM to DSD AES1 in as Auto with DSD out If you overwrite this store be careful when installing future software updates You can overwrite this setup Store 11 Preloaded with multi channel sync 44 1 kS s in as Auto to DSD out You can overwrite this setup store 12 Preloaded with multi channel sync 44 1 kS s in as Auto to 96 kS s out You can overwrite this setup Stored setups may be recalled from memory at any time Press the Recall button and the display changes to Default gt 36k gt CO Out gt Dual 96 Singdle UrFsamelirng Derma Empr t ZEmMe ts Scroll down to the required store and press the Enter button A message window will appear in the display to confirm that the unit is reading the setup When complete the display shows the Status screen for the current menu dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 lf you make a mistake during a Store or Recall routine and you have not yet pressed Enter you can abort it by pressing any of the 4 Operation buttons Locking Out Changes and Unlocking Again Once the unit is set up it may be locked against casual interference by holding down the Status button and pressing the Store button TEES appears on the right hand side of the Status Error Monitor Test Mode Info Bit Activity Monitor or Level M
22. a Setup The dCS 972 features 12 non volatile user programmable setup stores and one preset one that cannot be written to These are accessed by the rotary control and the block of four MEMORY buttons on the lower left hand corner of the unit First set up the unit as required then press the Store button The display will look similar to this 96k CO Out Dual 96 5in9le WrFsameling Emre ty Emp t a ZEmMe tL ZEmMe tg I E Ahi You can scroll down the list using the rotary encoder and reveal stores to 12 Notice that Store O the default setting store is not available you cannot overwrite this Scroll to the required store e g Store 10 and press the Edit button The display changes an alphanumeric screen is displayed with the current store name at the top and all of the legal characters below it as follows m Se vO OP de wz Turn the knob to move the Edit block backwards and forwards through the available characters The arrow T indicates which character you are editing and the character is updated in real time as you move the edit cursor The 1 symbol represents lt End gt When you have finished editing the character press the Edit button to return to the previous screen and select the next character to edit Names can be up to 16 characters long plus an lt End gt character to mark the end of the name If all 16 characters are used and you attempt to edit the lt End gt character i
23. be used to monitor DSD signals by setting a DSD to PCM conversion Even though the conversion may not be used the level metering will effectively meter the DSD input Display Controls the Brightness Contrast Cursor direction and Backlight timeout behaviour of the display dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Manual part no DOC1241102C2 Page 23 Document No OS MA A0124 110 2C2 Contact dcs on 44 1799 531 999 email to more dcsitd co uk inside the UK replace 44 with 0 web site www dcsltd co uk dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Sample Rate Conversion Format Conversion Submenu The Sample Rate Conversion menu is as follows Py Onwers lorn a Audio Inet Select Src SOW ce Multirle Channel Syrc TheWt Fresauwerncs Oubeut Freeswerncy utrut Mode Filter Audio Input Select Select the required input from the list and press Set The Dual AES option requires that the Inout Frequency be set to 192 kS s 176 4 kS s 96 kS s or 88 2 kS s Selecting DSD will select the SDIF set of inputs Sync Source Select a source to synchronise to from the list and press Set The available sync sources are AES AES Clock In the AES reference input Word Clock SDIF 2 Input Clk Audio Input Syncs to the selected input source this is the normal setting Internal Syncs to the dCS 972 s internal clock Lab Ref Syncs to a 10 MHz signal into SDIF 2
24. cccceeeeeecececececececececeeeees 8 44 BUOM FOC Al lisd Seocacs tint ace ater cant es see ane 8 44 BURON SC Wis tions terrae enenconetsee oN 17 36 BUON SIOC anasa xa veces castes Bees 43 45 Buttons MOMOTS cccccscceseceeeeeeceeeaeeeeees 14 Buttons Operation cccccceeceeeeeeeeeeees 14 17 C CIP GIG ALON aaa N 31 39 Cursor CUSLOMISING cccseccseeeeeeeeeeeeeeeees 42 D BDO rastreo aeaa 6 63 Digital SUCNICS niian a a 32 Display backlight timeout eee 42 Display brightness cccccceceseeeeeeeeeeeeeeees 42 DiSpIAV CONTASI eksisin eni 42 Display CUSTOMISING secceeeeeeeenees 15 32 Dither 30 33 72 80 81 90 91 93 94 Dither generators ccccccccsecceeeeeeceeeeeeeeees 72 Dither histogram seterrenth erga viecutidonatesversands 72 Dither NOISE POWET ccccccceeceeeceeeeeeeeees 72 Dither POF edera tina sade E 80 90 Dither weighted noise POWET 00808 72 DDSI ratoman 24 28 32 35 50 58 73 80 91 DSD data alignment ccccceeceseeeeeeeeeees 67 DSD TUM SCA r 84 DSB TDS Diss acacustedacss aiadeacena tens 25 DSD PR GV neeaae 22 39 41 DSD DCO removak sea awison 28 DSD Mtera N 28 83 BrE D R p e0 EEES EN A EE 10 28 DSD level metering 0nn0nn0nnn0ann 22 39 41 DSD OUMU rrn 28 E TrOr MONO eana edt 20 21 34 45 F Fite eree e tear taeseca ase 28 33 60 Filter CULOIT aeni
25. dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Size Weight and Operating Conditions Size and Weight The dCS 972 dimensions correspond to a standard 2U 19 rack mount case Four heavy duty feet fitted to the base extend the overall height to slightly greater than 2U Dimensions Width 430mm see note i Height without feet 88 mm 2U Height with feet 95 mm Depth 390mm see note ii Weight 8 5kg see note iii note i Removable 19 rack mount ears are supplied taking total width to 483 mm 19 note ii Measured from front panel to rear panel connectors Additional depth should be allowed to accommodate cable connectors The rotary control knob protrudes 22mm from the front panel note iii The high quality case is necessarily heavy consideration should be paid to appropriate support shelving when installing the units in a rack Operating Conditions The case of the dCS 972 has no ventilation slots or fan cooling to give e quiet operation does not need to be installed in a machine room e internal temperature stability e improved electrical safety e long term reliability e no regular maintenance or cleaning requirements It dissipates relatively low power so that usually allowing natural convection provides enough cooling Do not install the unit near heat sources such as radiators air ducts or direct strong sunlight Ambient should not exceed 50 C should not fall below 0 C
26. highest quality clocks that are available are crystals so we use these In Master mode the dCS 972 uses one of two on board voltage controlled crystal oscillators VCXOs as clock sources one for 48 kS s related outputs and one for 44 1 kS s related outputs The internal VCXO is synchronised to the sync source which ned not be the signal input by a phase locked loop PLL The PLL is of a special narrow bandwidth type that provides a significant degree of clock cleaning but even so signal quality may degrade if particularly poor slave clocks are used A consequence of the narrow bandwidth is that it takes quite a long time for the PLL to lock to a new clock frequency of the order of 2 seconds The PLL uses DSP assistance to keep this time acceptable The input data is extracted using an oversampled UART type of decoder This can tolerate quite jittery inputs whose phase is unrelated to the clock source used for locking The average frequency must be the same however Accuracy when shipped 10 ppm Long Term Stability 10 ppm year at room temp Temperature Stability 15 ppm over operating temperature range Synchronising to source Pull in range 300 ppm about nominal frequency Lock in time lt 2 seconds for most combinations The PLL is very robust and will lock to very poor signals if necessary Data is decoded using a much wider band faster PLL so AES3 type low frequency jitter on the input clock can be handled and
27. its statistics can be controlled and the converse effect of the signal modulating the dither can be made insignificant or zero However there are a number of ways that this dither signal can be generated and treated The major options are e it can be generated from the signal or generated independently and added Dither It seems implausible that the dither signal can be generated from the signal but it can and this gives the lowest added noise power option It is noise shaping on its own but there are some circumstances where it needs help from additional dither e it can be added inside or outside an error shaping loop e it can be frequency shaped to match the ears response or not We can use techniques that suppress error energy in the areas where the ear is sensitive and put it in areas where the ear is not sensitive Usually this shuffling around process costs us we remove a little from the sensitive areas and add back rather more in the less sensitive parts but that s life We still gain some improvements The table below gives the actual noise levels for 16 bit truncated signals with no dither various dither types noise shaping alone and noise shaping with dither The O dB reference level is taken as the minimum noise we could possibly get away with the amount that simple 16 bit truncation 16 bit Q noise would give if it were well behaved which it is not 2 PDF Probability Distribution Function Refere
28. kS s conversion Filter responses Noise shaping curves for 32 kS s Noise shaping curves for 44 1 kS s Noise shaping curves for 48 kS s Noise shaping curves for 88 2 kS s Noise shaping curves for 96 kS s Noise Shaper noise and weighted noise vs shaper order Histograms of Dither Types before Truncation dCS 972 SW v1 54 MAM Y Al pheta AAD a AY yd gy Aa Top Hat Triangular Noise Shaped Triangular 256 128 0 128 256 384 Code Isbs Figure 25 Dither PDFs dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Dither Only Spectra no Signal dCS 972 SW v1 54 110 Wwe anan A An palma SANSA 2 JV m ke D Top Hat dither actual theoretical gej 5 130 i Triangular dither actual theoretical F Noise Shaped Triangular dither actual theoretical 140 150 0 2 4 6 8 10 12 14 16 18 20 22 Frequency KHz Figure 26 Dither Spectra FFTs Raw Data for Source and Truncated Small Signal dCS 972 SW v1 54 2048 1024 ji n ee 3 Lu Ibu M g o lu MAIN I z AVA NM 1024 24 bit source data 16 bit truncation 16 bit truncation with Top Hat dither 16 bit truncation with Triangular dither 16 bit truncation with Noise Shaped Triangular dither 2048 0 128 256 384 512 Sample Number Figure 27 Small Signal Raw Data with Dithers dCS 972 User Manual Manual for Software Version 2 3x dCS
29. not locked to a valid digital input Rotary encoder Turn the knob to move up down the menu tree adjust parameter values or edit store names The user may select whether clockwise rotation moves the cursor up or down see the section on Display Customise page 32 The unit is shipped with the cursor moving downwards by clockwise rotation of the knob and all instructions in this manual refer to a unit in this configuration We recommend turning the knob at a steady speed rather than trying to turn it as fast as possible Power LED The LED in the top left hand corner lights when power is applied dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Navigating through the Menu what the On Screen symbols mean Once the unit has powered up and the Status screen is displayed you can start navigating through the menu This section explains how the keys operate and what the various on screen indications mean To start pressing either the lt or button brings up the top level of the Menu ate Lonversion Formai Convers iorn Error Monitor Test Info o Bit Activita Monitor Level Meters Disrelay The I symbol is the cursor and an indication that there are sub menus available below this level If there are no more submenus it changes to W Turn the rotary control clockwise and the cursor will move down the list Turn the rotary control counter clockwise and the cursor will move back up To access the Sam
30. referring to sample rates SQNR Signal to Q noise ratio dCS 972 User Manual dCS Ltd Full Contents The Hardware Controls and Connectors Rear Panel The Software Menu and Setups Top Menu Manual for Software Version 2 3x Product Features About this Manual Using Your dCS 972 For The First Time Product Overview What s in the Box Mains Voltages Installing Unit in a Rack Getting Started Signal Inputs Signal Outputs Control and Power Additional Information Digital Data Formats Supported Front Panel OPERATION buttons MEMORY buttons LCD display LED indicators Rotary encoder Power LED Navigating through the Menu what the On Screen symbols mean Sample Rate Conversion Format Conversion Error Monitoring Test Info Bit Activity Monitors Level Meters Display Sample Rate Conversion Format Conversion Submenu Audio Input Select Sync Source Multiple Channel Sync Input Frequency Sample Rate Output Frequency Sample Rate Output Mode Filter Output Word Length Noise Shaping Dither AES Message Edit SPDIF Message Edit Gain Balance and Maximise Swap channels Phase Detect Silence De Pre Emphasis Display Customise Error Monitor Submenu Error Hold and Reset Test Submenu Generator Overview Controlling the Generator Generator Amplitude Adjustment Generator Frequency Adjustment Self Test Info Submenu January 2001 dCS 972 User Manual dCs Ltd Manual for S
31. select DSD SDIF 2 or DSD SDIF 3 and the unit will make the appropriate changes The unit supports DSD out with either DSD or PCM in DSD output includes a DSD DC blocking filter All signals in DSD or PCM will have their DC filtered out In this mode the 3 AES and 3 SPDIF outputs all carry identical AES streams with no data they may be used for synchronisation For PCM output select Dua AES to output a 192kS s 176 4kS s 96 kS s or 88 2 kS s AES3 signal on two cables AES1 and AES2 In this mode the AES Clk Output and 3 SPDIF outputs all carry identical AES streams with no data they may be used for synchronisation The SDIF Clk Output sends Wordclock do not use the SDIF data outputs while in Dual AES mode Otherwise set to Normal For PCM out the unit can have PCM or DSD in The dCS 972 offers a choice of filter for use on some of the more popular in out combinations The filters offer differing responses For PCM outputs Filter in each case offers the sharpest cut off and no or least aliasing but longest energy smear Filter 4 gives the gentlest roll off usually with significant aliasing but the shortest transient response with least smear For DSD output the differences are not so great the responses are given in the section dCS 972 Performance Curves page 80 The conversions that offer multiple filters are as follows Number of Filters Available Table 3 Conversions with Multiple Filter Options We enc
32. signal path from the selected input is disabled and replaced by the Test Generator signal The Generator is turned off and reset to 18 0dB at power down The last option on the test menu is Self Test this exercises the LEDs and the LCD display Select this and press Set If all is well the LEDs will flash in sequence and the LCD will display a pattern of flashing columns Press any button to exit from this dCS 972 User Manual dCS Ltd Info Submenu Manual for Software Version 2 3x January 2001 To display information about the unit return to the top level menu select Info and press Set The Info screen will be displayed Front Panel EEPROM we 38 Control Board EEPROM we 38 Control Board SH 606002 340 41 0624 d05 email dosddcoddcsltd co uk Conversions SurFrForted 9 Conversions with 1 filteri 5 The first three lines give important details about the hardware and software in your dCS 972 This is helpful if you experience difficulties with your unit Line four is dCS E mail address for use if you need any further assistance The last two lines give you a hint of the options available on your machine Bit Activity Monitor Submenu Bit Activity Monitoring Overview Setting the Monitor This monitors activity on the selected input and indicates the wordlength of the data provided by the source device Because the monitor works on the input it can be used for DSD outputs if the input is PCM To monitor the output u
33. they may be AES Message Edit SPDIF Message Edit overwritten Sample Rate Conversion On Audio Input Select AES 1 sync Source Audio Input Input Frequency 96 kS s Output Frequency 44 1 kS s Output Mode Normal Filter Filter 2 Output Wordlength 16 Noise Shaping 2nd Order Dither Noise shaped triangular Detect Silence On Professional Off Non Audio Off Mode Stereophonic Professional Off Non Audio Off Copy Permit On Format Compact Disc dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Demultiplexing a 24 96 Dual AES recording Bit for Bit From 24bit 96kS s Misue AESI amp AES 24 bit 96kS s from 3 Dual AES source are connected correctly independent AES outputs AESI Left data AES2 Right data AES1 AES2 AES CLK CH1 CH2 CEK g b T AES EBU Outputs MAINS FUSE 2A T ON OFF SPDIF1 SPDIF2 SPDIF3 E 24 bit 96kS s 24 bit 96kS s from 3 SDIF 2 output independent SPDIF outputs Figure 4 Converting dual AES 24 96 to a single wire double speed one The dCS 972 converts a 96 kS s 24 bit Dual AES input to a double speed 96 kS s 24 bit signal available from any or all of the 3 AES 2 SPDIF or SDIF 2 outputs When using the Format Conversion menu the operation is bit for bit on the audio data messages can be edited Connect Nagra D Genex G 8000 SADIE Lake DSP etc dual AES source to inputs AES 1 and AES 2 on the dCs 972 load the setup fro
34. 1k 48k 88 2k or 96kS s or Dual AES at 88 2k 96k 176 4k or 192kS s or DSD Figure 6 General Sample rate Conversion The dCS 972 converts any one of 12 sampling frequencies in any format to any of the 12 sampling frequencies in ALL formats 3 AES 2 electrical SPDIF optical SPDIF or SDIF 2 outputs Most frequency combinations including all the primary ones are accommodated in one pass see the table in Table 2 One Pass and Two Pass Conversions on page 26 For best results the unit should be slaved to the active input the AES Clock Input or the SDIF 2 Word Clock Input Connect any digital audio source of any word length between 8 and 24 bits using single or dual wire AES to the AES inputs or using single or double speed SDIF 2 to the SDIF 2 inputs or using single wire SPDIF to the appropriate SPDIF input Select Audio Input accordingly Output via any of the outputs Sample Rate Conversion settings Sample rate Conversion On Audio Input Select Any even including Dual AES if the Input Frequency is any of 192kS s 176 4 kS s 96 kS s or 88 2 kS s Output Mode Normal or Dual AES may be selected if the Output Frequency is set to 96 kS s or 88 2 kS s Dual AES must be used for 192kS s_ or 176 4 kS s Other settings Any 2 It has to be Dual AES for 192 kS s or 176 4 kS s dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 PCM to DSD From PCM in ANY format AES SPDIF Toslink
35. Dither or Detect Silence or both The LCD display is unreadable but the Power LED and possibly some other LEDs are lit e Disolay Contrast may have been set to minimum Switch off the unit wait 10 seconds hold down the Status button and switch on The unit will power up using default settings including high contrast Alternatively Store O Is pre loaded with default settings Press Recall and Enter to recall from it Strange characters appear on the LCD display e This can be caused by power line drop outs or switching the unit off and on rapidly Switch off wait 10 seconds then switch on normal operation should be resumed The stereo image is poor or out of position e Check that Phase and Swap Channels are set to Normal e Check that Balance is correctly set e It may be that the input signals are out of phase swapped or out of balance Use the units controls to correct this e f using the SDIF 2 interface the Ch1 amp Ch2 cables may be swapped e f you are using a Dual AES mode from some other equipment make sure you used the right outputs from that Maximise fails to increase the signal level to full scale e The range of the Maximise function is limited to 12dB If the input signal peaks are smaller than 12dBO Maximise will apply 12dB of gain A second pass will apply up to 12dB more gain dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 When setting Input Frequency or Output Freque
36. Hz Figure 43 Truncation Only Spectra dCS 972 User Manual dCS Ltd Noise Power dB rel no shaping Manual for Software Version 2 3x January 2001 When is Dither Needed 30 24 24 30 36 42 48 Dither on its own or with noise shaping is not always needed The condition for not being needed depends on the level of noise in the incoming signal the amount of noise shaping being used and the output word length The user may want to avoid having to think about this at all in which case use Noise Shaped Triangular dither or may wish to minimise noise and added noise As a rule of thumb if the following condition is met dither is not necessary Noise in input y Noise gain of Z Q noise of wanted signal noise shaper output word length The noise gain of the noise shaper is the same as the unweighted noise power given in Table 11 and is shown in Figure 44 below Noise Gain and Weighted Noise Gain vs Shaper Order dCS 972 SW v1 54 Actual Increased Noise Power and Noise top section Gain i o 96 kS s 088 2 kS s m 48 kS s 44 1 kS s 532 kS s Perceived F Weighted Noise Power bottom section oI 2 3 4 5 6 7 8 9 10 Noise Shaper Order Figure 44 Noise Gain and Weighted Noise Gain by Shaper Order and Sample Rate As an example of reading this consider a 24 bit signal in with a 110 dBO noise floor to be output at 48 kS s 16 bits
37. Input Clk For best results synchronise to the Audio Input or a master clock on one of the clock reference inputs that is also driving the source For DSD a Word Clock must be used contact dCS if you need a Bit Clock The Lab Ref setting allows use Of a GPS reference if you use this make sure other parts of your system are also GPS sync Only select Internal sync if you are using the unit as a signal generator or a reference clock source Multiple Channel Sync This option is either On or Off ate Lonversion sMultiele Channel Sunc E rn The unit uses the AES Clk Input as a sync link When On if the unit detects a sync signal into the AES Clk Input it will sync to it and set up as a Slave If there is no sync signal coming into the AES Clk Input it will set up as a Master see section Multiple Channel Sync ing page 68 for an explanation or the section Multi channel Sample Rate Conversion bit aligned sources page 52 for wiring Do not feed a signal with active User bits into the AES Clk Input with Multiple Channel Sync turned on dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 When the option is On the Status display informs you about the unit s configuration If an active signal is connected to the AES Clk Input but it does not carry User bits the unit thinks it is a Single unit and the Status display is as follows Ot Ad 1 k s InFut AESI San Audio Input OP Mode Horm
38. Model Number dCS 972 Manufacturers Name and Country of origin dCS Ltd UK The underside of the unit will have a label on that contains a number such as 972 4B1 6B2 2A1 3A2 12345 This is the serial number but it also contains vital configuration information We will need this number all of it to give you support over the phone or to ship you software updates dCS 972 User Manual dCs Ltd Manual for Software Version 2 3x Digital Data Formats Supported 3 January 2001 The unit provides six digital data i o formats AES EBU often referred to as AES3 for PCM operation Dual AES part of the AES3 spec for PCM operation SDIF 2 for PCM operation SDIF 2 for DSD operation SDIF 3 for DSD operation SPDIF electrical for PCM operation SPDIF optical for PCM operation For all formats the incoming Channel Status and User messages are discarded The unit allows the AES EBU and SPDIF output Channel Status bits to be edited The enhanced AES EBU interface is fully implemented Each channel has its own parity and data validity bit as well as User and Channel Status messages Cyclic Redundancy Counts CRC s are generated from the Channel Status message The Dual AES interface allows a 96 or 88 2 kS s 24 bit signal to be coded as two standard 48 or 44 1 kS s 24 bit AES data streams recorded as two channels on a recorder with standard capacity replayed and decoded back into a single data stream Operation of the Dual AES interfa
39. Passband Response dB 0 100 0 075 0 050 0 025 0 000 0 025 0 050 0 075 0 100 0 125 0 150 0 175 0 200 0 225 0 250 0 275 0 300 0 100 0 075 0 050 0 025 0 000 0 025 0 050 0 075 0 100 0 125 0 150 0 175 0 200 0 225 0 250 0 275 0 300 Manual for Software Version 2 3x January 2001 48 kS s to 44 1 kS s Filters dCS 972 SW v1 54 Filt 1 Filt 2 4 41 8 82 13 23 17 64 22 05 26 46 30 87 Frequency kHz Figure 34 48 kS s to 44 1 kS s conversion Filter responses 96 kS s to 44 1 kS s Filters dCS 972 SW v1 54 Filt 1 _ Filt 2 i l f N Hi Mi WI 4 41 8 82 13 23 17 64 22 05 26 46 30 87 35 28 39 69 44 1 Frequency kHz Figure 35 96 kS s to 44 1 kS s conversion Filter responses Response dB Passband Response dB dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Noise Amplitude relative to No Shaping dB Noise Amplitude relative to No Shaping dB 24 36 30 24 18 32 kS s Noise Shape Plots dCS 972 SW v1 54 2nd or 6th Order Recommended Kg amp Order 1 Order 2 Order 3 Order 4 Order 5 9 Order 6 Order 7 Order 8 Order 9 Order 10 0 4 8 12 16 Frequency kHz Figure 36 32 kS s noise shaper curves 44 1 kS s Noise Shape Plots dCS 972 SW v1 54 2nd or 9th Or
40. RMATION DSD Filter Options DSD is a single bit very high sample rate 2 822 MS s format where the single bit words are heavily noise shaped to push noise energy above audio The frequency response is very high well above 100 kHz although at these high frequencies noise is also present For SACD purposes 0 dBOpsp is set at 6 dB below the peak to peak level one might expect a full scale sinewave to occupy this ensures that artefacts that begin to occur at the limits of the DSD amplitude range do not move down into the audio band The 0 dBOpsp level is shown graphically in Figure 33 page 84 The dCS 972 offers a number of different DSD modulators as Filter options All the modulators have the same signal frequency response They differ in the way they shape the out of band Q noise and in how far they suppress the in band Q noise Filters to 5 suppress Q noise at least 120 dB below the nominal OdB DSD signal which is one of the marketing specs for SACD Filter Comments Stability Description High SQNR high stability 1 7 10 Two complex zeros High SQNR 8 2 10 Two complex Zeros High SQNR very high 1 5 10 Two complex Stability Zeros Extremely high stability 3 0 10 Two complex zeros Reduced 100k noise 7 1 10 Two complex Zeros Single complex zero 37710 Single complex Zero Real zeros 2 0 10 Real zeros only Table 4 DSD Filter Summary Signal to Q Noise and SACD Specs Although 120dB SNR ove
41. The Q noise in the output signal would be 98 dBO so if a noise shaper with more 12 dB of noise gain was used no dither would be necessary Looking at the chart a 5 order shaper 14 2 dB of noise gain would avoid the need for dither whereas a 4 order one 10 9 dB of noise gain would need dither The 5 order shaper would give a weighted noise improvement of 16 4 dB whereas the 4 would only give 13 9 dB perceived improvement less a further degradation from adding dither dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Manual part no DOC1241102C2 Page 95 Document No OS MA A0124 110 2C2 Contact dcs on 44 1799 531 999 email to more dcsitd co uk inside the UK replace 44 with 0 web site www dcslitd co uk dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 OPTIONS The following options may be fitted to new units or retrofitted at a later date Locking to video sample rates Mains voltage set to 230 240V Mains voltage set to 215 220V Mains voltage set to 115 120V Mains voltage set to 100V Table 12 Options available Locking to Video Sample Rates We can fit additional video frequency VCXO s enabling frequencies such as 44 056kS s and 47 952kS s This option must be fitted at dCS to allow full checking Contact dCS for details Mains Supply Voltage Any unit may be set for operation from 230 240V 220V 115 120V or 100V A C The voltage setting can be updated
42. WORDCLOCK IN Hand Crafted by The Red Hot CD Player Co 16bit 44 1kS s E e 2 3 PPa 4 n ains Fuse 2AT On Off AES REF to other system components y y y y y y y y dCS 992 96kS s Master Clock Wordclock to other system components AES1 AES2 AES CLK 3 AES1 AES2 AES CLK Ops Qe Jesse e SDIF 2 Output Dual AES up to 24 bit 192kS s AES EBU Outputs MAINS FUSE2A T ON OFF SPDIF Outputs CHIL OkO Ace Analogue dCS 954 24 192 DAC or Elgar or Delius Balanced Unbalanced Analogue Analogue Outputs Outputs Figure 8 Using a Master Clock If a Master Clock such as a dCS 992 is available and the driving source is locked to it the dCS 972 may be locked to it Either connect the Master Clock to the AES CLK Input and select AES as the Sync source Or connect the Master Clock to the SDIF 2 CLK Input and select Word Clock as the Sync Source IMPORTANT Since the Output Frequency of the dCS 972 is different to the Master Clock frequency the DAC would be unable to lock to the data from the dCS 972 if it were sync ed to the Master Clock So slave the DAC to the dCS 972 NOT to the Master Clock dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Multi channel Sample Rate Conversion bit aligned sources 96kS s Chl amp 2 96kS s Ch3 amp 4 44 1kS s SOURCE 96kS s Ch5 amp 6 96kS s Ch7 amp 8 Figure 9
43. al U Length 24 bits H Share OFF If no signal is connected into the AES Clk Input there is no sync link going in the unit thinks it is a Master and the Status display is as follows Ost Ad 1 k5rs InFut AESI Syne Audio InFut O P Mode Hormel Haster U Length 24 bits Gain 4 Ade H Share OFF Bal L dE F Ade If the sync link is connected and active the unit thinks it is a Slave and the Status display shows Oat fa pal 1 kS s Infut AESI Audio ITnrFut Mode Hormel Slave U Length 44 bits Gain 6 H Share OFF Bal L HJE E F d AJE For multi channel syncing on DSD to DSD the sync link does not synchronise all the output Word Clocks Each unit will have a different phase Just use the Word Clock from one unit and ignore the rest the group delays for the signals will not be affected Input Frequency Sample Rate For PCM operation the input sample rate can be sensed and set automatically using the Auto option or forced The latter is useful where use of 1 or 2 wire mode for higher sample rates might be ambiguous otherwise Auto is best It occurs at the bottom of the Input Frequency list e Rate Lonversion Ineut Fresauency 24k 5 5 77 Wok 5s Bk S s Fi 1 1fk 5 5 11 H25k 5 5 Bauta O dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Select the required entry from the list and press Set If you have selected Auto then the list changes whe
44. ame frequency for block structuring to work no Master Clock Input misalignment allowed 324 with all inputs at the same frequency with Master Clock Input misalignment allowed 11338 5208 with all inputs at the same frequency with Master Clock as in Figure 12 The scope shots below show the timing relationships between two units using the sync link for various conversions They are taken from 2 units with scope probes on the same point in each unit The units are linked by a sync link 2 version 2 0 software or higher Ul Unit Interval see AES3 spec There are 128 Ul s per sample in AES3 Master Clock can adjust its Word clock phases as necessary dCS 972 User Manual dCs Ltd Manual for Software Version 2 3x January 2001 AS running 1 3 00 Wediv BA lim 56 250 10 00 1 1M de i 2 5 00 Vidi TT E a aa A a 10 00 1 IM de 1 0000 us 0 000 g 1 0000 us 200 ns div repetitive Trigger Mode Edge E 2 500 Figure 22 44 1 kS s to 96 kS s PCM showing AES3 alignment fe running 1 3 00 Wediv BA lim 56 250 10 00 1 1M de sala a E a a ee a Ma e i a a a UM Sas a a OA ca a a pte See Wis ae ee A A aoa a aa a a a e Se ie 2 5 00 Vfdiv BH lim 8 000 10 00 1 1M amp de CY E O 000 2 2000 Us J00 ns div repetitive Trigger Mode Edge 7 5000 us E 2 500 Figure 23 96 kS s to 44 1 kS s PCM showing AES3 alignment dCS 972 User Manual Manua
45. and should be non condensing If in doubt the easy test is the dCS 972 is happy to work anywhere a human is dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Manual part no DOC1241102C2 Page 9 Document No OS MA A0124 110 2C2 Contact dcs on 44 1799 531 999 email to more dcsitd co uk inside the UK replace 44 with 0 web site www dcsltd co uk dCS 972 User Manual dCS Ltd Manual for Software Version 2 3x January 2001 dCS 972 PERFORMANCE CURVES Fraction of Time Dither Occupies Bin 0 5 0 4 0 3 0 2 0 1 0 0 384 The graphs on the following pages show key performances of the dCS 972 Dither PDFs showing how the dither types are effectively ideal including noise shaped triangular dither FFTs of the dither signals used excludes truncation or Q noise e Raw data for small signal truncated 4 Isbs sinewave showing source waveform no dither and all dither types Shows absence of DC offset and behaviour of the various dithers FFTs of truncated small signal 90 dBO sine showing no truncation truncation without dither and the effect of dithers FFTs of truncated small signal 90 dBO sine with noise shaping with and without added dithers DSD spot Q noise for filter options DSD integrated Q noise for filter options DSD F weighted Q noise for filter options DSD 0 dBO full scale signal 48 kS s to 44 1 kS s conversion Filter responses 96 kS s to 44 1
46. at the address below within 30 days of the sale dCs Ltd Mull House Great Chesterford Court Great Chesterford Saffron Walden CB10 1PF U K Serial No 972 located on the underside of the unit Name of new owner Date purchased Website Name of registered owner Signed x
47. ate in FC mode FC mode has no 0dB signal drop and will not allow operations that can cause audio data bit changes but it does allow bit for bit copies of signals to be made in different digital formats It also allows message editing but many of the other options available in SRC mode are removed from the menus while FC mode is active SRC mode offers all the options of FC mode FC mode just turns off the options that affect bit for bit performance There are no options that are just available in FC mode Sample Rate Conversion Format Conversion 4 The default setting is Sample Rate Conversion SRC mode on Format Conversion FC mode Off Pressing will enter the Sample Rate Conversion menu e ka OnVvers lor kondia THeut Se ect Syric Source Hultirle Channel Syrc Tneut Freasenca Quteut Fresuencd Dutert Mode Filter The default setting is SRC mode on FC mode Off To turn FC mode on select Format Conversion and press gt The menu below will appear in older versions of software this was 0 1dB dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Onwers 1Or Pure Format Conversion OFf Audio Input Select Sync Source Multirle Channel Syne TReuL Fresauency Dutrut Mode l HES Message Edit Pressing Set will toggle the state from Off to On The unit will check to see if the Output Frequency is the same as the Input Frequency and if it is not it asks you to press Set to chang
48. automatic gain setting to get the highest possible level without overload for CD preparation for example The balance control works in a different way to conventional analogue balance controls and although is easy to operate you should be aware of what it does To set the gain select Gain then press Set Turn the rotary control to adjust the Gain anywhere between 100 0 dB and 12 0 dB in 0 1 dB steps Press Set again to exit IMPORTANT Use positive gain with care as the unit does not monitor overloads If in doubt use Maximise instead With Balance set central i e L OdB R OdB no gain is applied to either channel Panning to the right attenuates the left but does not amplify the right channel and vice versa This arrangement helps avoid overloads To set the balance select Balance then press Set Turn the rotary control to adjust the balance anywhere between 0 0 and 6 0c8 on either channel in 0 2dB steps Adjustment beyond 6 0dB mutes that channel Press Set again to exit Maximise is a feature that makes best use of the available dynamic range The dCS 972 keeps a running record of the maximum amplitude of the signal Maximise can then apply the exact gain to ensure the highest signal peak noted is boosted to full scale The maximum gain that may be applied is 12dB If the correction exceeds this 12 0dB of gain will be applied Please note that Maximise cannot correct overloads Maximise can be run repeatedly if y
49. ays away at 11 ms segment Instant the bar length decays away completely in 32ms Select the required Decay Time and press Set Peak Hold Select Peak Hold and press Set to display the Peak Hold options Level Meters Peak hold Infinite BReset The unit notes the highest signal peak on each channel and turns on the appropriate meter segment on each bar The Peak Hold segment remains for the set time and is then replaced by the next signal peak dCS 972 User Manual dCS Ltd Manual for Software Version 2 3x January 2001 The menu options function as follows None Disables the Peak Hold feature 320ms thru 1600ms Sets the Peak Hold time Infinite Sets an infinite Peak Hold time Reset Resets the Peak Hold segments to the current peak Select the required option and press Set Infinite allows the highest peaks in a track or long passage to be displayed you might want this to do a manual maximise Select Infinite and press Set At the start of the track select Reset and press Set Press Status to display the meter At the end of the track the highest peaks will be displayed Select Reset again and press Set to clear the peak readings Using the dCS 972 to monitor a track If you just want to use the dCS 972 as a level monitoring device you can control the bandwidth you monitor by setting the output data rate 44 1kS s will give approximately 20 kHz bandwidth whereas 96kKS s will give approximately 40 kHz bandwidth
50. bit multiplex demultiplex mode PCM to DSD DSD to PCM DC Removal for DSD Multiple filters on many major sample rate conversions Dither 3 types Noise shaping 10 different options on all major PCM sample rates Output Level control with Maximise Balance control Digital Silence out with digital silence in Monitoring Bit Activity Stereo Level and CRC Parity amp Invalid flag errors in the input data Test Generator High quality 160 dB signal generator with mHz resolution Can be dithered and or noise shaped truncated Ease of Use User programmable set ups Pre loaded setups Remembers last settings Lockouts dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Contents Product Features 3 About this Manual 5 Using Your dCS 972 For The First Time ccccseccsseeeseeeeeeeeeeeeeeeeseeeeeeeeeeeees 6 Product Overview 6 What s in the Box 6 Mains Voltages 6 Installing Unit in a Rack T Getting Started 8 The Hardware Controls and CONnNeCtolrs cccccecceseeeeeeeeeeeeneseeeeeneeeneeenes 10 Rear Panel 10 Digital Data Formats Supported 12 Front Panel 14 Navigating through the Menu what the On Screen symbols mean 16 The Software Menu and Setups ccccccceseeeeeeeeeeceneeeneeeneseneseneoneseeeeseeees 18 Top Menu 20 Sample Rate Conversion Format Conversion Submenu 24 Error Monitor Submenu 34 Test Submenu 35 Info Submenu 38 Bit Activity M
51. ce at double speed allows the unit to input or output 2 wire 192 kS s 24 bit data and convert to and from this SDIF 2 PCM message bits are internally set to zero with the exception of the block code which is implemented The SPDIF interface has no CRC s as per definition Data formats for both SPDIF electrical and SPDIF optical are identical DSD has at the time of writing no messaging structure Contact dCS for more details Data formats use either the SDIF 2 system two data channels and third clock channel or the SDIF 3 format two data channels with embedded clock At present we do this because there is no standard on what to do with the excess or shortage of bits that is created by a sample rate change If this causes you a problem call us we can probably do something else if we are clear what that ought to be dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Manual part no DOC1241102C2 Page 13 Document No OS MA A0124 110 2C2 Contact dcs on 44 1799 531 999 email to more dcsitd co uk inside the UK replace 44 with 0 web site www dcslitd co uk dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Front Panel BIT 96 OPERATION D et Status MEMORY TO Store er TENE dCS 972 D to D Converter Figure 2 Front Panel Because of the many options on the dCS 972 we have used a menu based system to control it The hardware buttons and k
52. d January 2001 Error Monitor Submenu The dCS 972 keeps count of CRC Parity and Invalid errors and displays them on the Error Monitoring screen To view this go to the top level menu select Error Monitor and press Status Error Monitoring CEC Errors LHE B Parity Errors LHF amp Invalid Flags LHE amp This shows the error count on Left and Right channels separately since the last reset Error Hold and Reset Select the Error Monitor menu and press gt to display the next level menu Error Monitor PLEC Errors Left CRO Errors Right Parity Errors Left Parity Errors Right Invalid Errors Left A Errors Right Press again to display the options for CRC Error Left Error Monitor Errors Left old keset Select either Hold or Reset and press Set The screen display changes to the Error Monitoring status Hold stops the count for that error type and Reset sets the count to zero Each error count may be stopped or reset in this way The All menu applies the changes to All Errors dCS 972 User Manual dCS Ltd Test Submenu Generator Overview IMPORTANT Manual for Software Version 2 3x January 2001 The dCS 972 includes a high quality digital signal test generator with both sine or Square wave outputs and displays its settings on the Test Mode screen When invoked the generator adjusts its output format to that currently operating and substitutes the generated output for any input signal T
53. d the Unlocked LED will light The screen will then display the Status Screen for example Out 44 1 k S s Inreut AESI Audio InPut Modes Hormal l W Length z4 bits Gain 8 8dB H Share OFF Bal L AdE F AdE Connect a signal source to an appropriate input AES 1 or 2 SPDIF1 2 or 3 or SDIF 2 CH1 CH2 amp CLK we recommend an AES3 source into AES 1 until you are happy with the unit Press the Recall button The display will change to Default 96k gt CO Ot gt Dual 36 7 Single UrFsameling sEmPp t gt EMEA EME Select Store O the default setting with the rotary knob and press the Enter button A message window will appear in the display to confirm that the unit is reading the setup Then when complete the message will go away the unit will lock and the Unlocked LED will go out The display then shows the status screen for the default setup as below if you have a 96 kS s source connected to AES 1 otherwise the left hand number will adjust to what you have connected Ost AA l bk 5s InFut AES Sync Audio InPut OP Mode Hormal HU Length 44 bits H Share OFF dCS 972 User Manual dCs Ltd Manual for Software Version 2 3x January 2001 The converted input signal will now be available at all of the outputs Connect the output of your choice to the input of a 44 1 kS s recorder DAC or other equipment you wish to drive It will now lock to the dCS 972 Note that all the outpu
54. d then as the level of the signal sinks below the Q level much error power piles into the fundamental This causes its amplitude to become unpredictable it may drop abruptly to zero and disappear or it may cease to go down any more and just stay at a constant level From the audio viewpoint this sounds very unpleasant As a signal tail decays away the tonal quality changes and then it decays into distorted mush and either abruptly stops or else keeps fuzzing away until a new signal starts The level at which all this happens is the Isb of the output word for CDs it is at the 16 bit level which equates to about 90 dBO The level is high enough to be quite audible and the effect must be tackled to make reasonable quality CDs There is really only one way of tackling the problem another signal has to be added to the wanted one to smooth the staircase transfer function that truncation causes Mathematically with two signals present the transfer function the wanted signal sees is the convolution of the PDF of the second signal and the staircase function The converse is also true the transfer function the additional signal sees is the convolution of the PDF of the wanted signal and the staircase function This aspect is not a problem with the dither types considered below but it can be with some highly frequency shaped dithers The additional signal is usually referred to as dither and it is usually noise like because then
55. d then carries on down units as shown Use of the master clock allows more units to be used together 24 channels worth or more For all dCS 972 units set the Multi channel Sync option to On They will all set up as slaves Make sure that all the other settings are the same on each unit S version 2 0 or higher software dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Multi channel Sample Rate Conversion with more alignment tolerance WORDCLOCKS TO SOURCES dCS 992 Master Clock 96kS s Chl amp 2 FROM SOURCE 96kS s Ch3 amp 4 96kS s Ch5 amp 6 FROM SOURCE 96kS s Ch7 amp 8 e2 LEESE a SS tD Figure 11 Multi channel Sample Rate Conversion with more alignment tolerance A dCS 992 Master Clock can also be used to sync up the source and the dCS 972 units as above In addition to the sync link cabling starting with A additional clocking cables C allow the dCS 972 s to extract clocks from the C cables and extract the data from the signal input cables The master clock outputs different frequencies on the different cabling types This allows considerable bit alignment error as might occur if some tracks are stored on one machine and some on another For all dCS 972 units set the Multi channel Sync option to On They will all set up as slaves Make sure that all the other settings are the same on each unit 14 version 2 0 or higher software dCS 972 Us
56. dCS 972 Digital to Digital Converter User Manual Software version 2 3x January 2001 1997 1999 2000 2001 dCs Ltd All rights reserved Reproduction of this manual in any manner whatsoever without the written permission of dCS is strictly forbidden Additional copies of this manual may be obtained from dCs Information contained in this manual is subject to change without notice and whilst it is checked for accuracy no liabilities can be accepted for errors 1 dCS Ltd is Data Conversion Systems Ltd Company registered in the England no 2072115 dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Manual part no DOC1241102C2 Page 2 Document No OS MA A0124 110 2C2 Contact dcs on 44 1799 531 999 email to more dcsitd co uk inside the UK replace 44 with 0 web site www dcslitd co uk dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Product Features Formats DSD and PCM from 192 kS s down to 11 025 kS s PCM data formats supported are AES EBU XLR Dual AES XLR SPDIF Phono Toslink and BNC and SDIF 2 DSD data formats supported are SDIF 2 and SDIF 3 Converts double speed 88 2 amp 96 kS s AES3 SPDIF or SDIF 2 into Dual 2 wire AES3 and vice versa Syncing Comprehensive can sync to Word Clock or AES reference or signal and sync to video option available Functions Sample Rate and Format Conversion Multichannel Sync capability Bit for
57. der Recommended Order 1 o Order 2 Order 3 Order 4 Order5 Order 6 Order 7 Order8 Order9 Order 10 0 4 8 12 16 20 Frequency kHz Figure 37 44 1 kS s noise shaper curves dCS 972 User Manual dCS Ltd 48 kS s Noise Shape Plots dCS 972 SW v1 54 36 30 24 Noise Amplitude relative to No Shaping dB Noise Amplitude relative to No Shaping dB 18 2nd or 8th Order Recommended 36 0 4 8 12 16 20 Frequency kHz Figure 38 48 kS s noise shaper curves 88 2 kS s Noise Shape Plots dCS 972 SW v1 54 36 30 24 18 12 T e 6 Manual for Software Version 2 3x January 2001 hy S Order 1 e Order 2 Order 3 Order 4 Order5 Order 6 Order 7 o Order 8 Order 9 Order 10 Q 24 00s QrQ 01 010202 O1 O10 1020102 21020501010 OOOO Qn Qn020 0 3rd or 7th Order Recommended 0 4 8 12 16 20 24 28 32 36 Frequency kHz Figure 39 88 2 kS s noise shaper curves _ Order 1 Order 2 gt Order 3 _ Order 4 Order 5 Order 6 o Order 7 Order 8 Order 9 Order 10 40 44 dCS 972 User Manual dCs Ltd 12 Noise Amplitude relative to No Shaping dB Actual Increased Noise Power top section Noise Power dB rel no shaping Perceived F Weighted Noise Power bo
58. dy turn around please contact us prior to returning the unit Safety and Electrical Safety There are no user serviceable parts inside the dCS 972 and so there is no need to remove the covers apart from front panel software updates If for some reason you do IMPORTANT Disconnect from the mains before removing any covers or changing the fuse There are no substances hazardous to health inside the dCS 972 dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 TROUBLESHOOTING FAQs The unit fails to lock to a source signal e Check that Audio Input Select is set to the correct input e Check that Input Frequency is either set to Auto or set to suit the source device e Check that Sync Source is set correctly try setting it to Audio Input e Check for damaged cables The unit locks but no signal is received e Display the Bit Activity Monitor to see if a signal is available at the unit If there is no signal into the unit and Auto Mute on there will be no signal out even with Dither and Noise Shaping on e f the unit is locked to an external clock check that Audio Input Select is set to the correct input e If SDIF 2 is used check that Ch1 and Ch2 are both connected The destination device fails to lock to the unit e Check that the unit is locked to a source e Check that Output Frequency and Output Mode suit the settings on the destination device e Ensure the destination device is set
59. e SPDIF interface have similar data structures although the messages are completely different The two structures are identified in the data domain by the use of the Consumer Professional bit bit I in the message A I indicates AES EBU format a 0 indicates SPDIF format The default AES EBU message attached to the output data by the unit before being changed by the user is as follows Professional On Non Audio Off Mode Stereophonic Source DCS1 Destination null For more information on the way dCS implement the AES3 system message to handle higher sample rates see the Appendix to this manual For the formal definition of the AES3 interface see footnote from the AES 28 AES3 1992 ANSI S4 40 1992 AES Recommended practice for digital audio engineering Serial transmission format for two channel linearly represented digital audio data dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 SPDIF Message Handling The SPDIF interface sometimes known as the Consumer AES EBU interface transmits a data structure that conforms to the IEC 958 standard Like the AES EBU this contains 28 bits of Manchester encoded data and a 4 bit near Manchester encoded preamble in a subframe and subframes are further assembled in a block and frame structure The difference lies only in the voltage levels and the Channel Status bits the System Message It contains 24 bits of audio data IMPORTANT The AES
60. e Version 2 3x dCS Ltd January 2001 Maintenance and SUD DONE i coiisssicciccdsicdsceysncssiuzitnensesdansisaspiwenesevndennauniesncseniianeess 98 Hardware 98 Software 99 Warranty 100 Update or Calibration 101 Safety and Electrical Safety 101 Troubleshooting scsiccscciiesedeicte sien pnwetacewenndecndecivicsmoeanvuonsbescdenddesdvecnviawdtancetandecnss 102 FAQs 102 If You Need More Help 105 Other Information 105 Indexes and Software Version Numbers cccsceseeeeeeeeeeeeeeeeeeeeeneeeneeenes 106 Owner Registration Transfer 113 About this Manual Note that there is a Full Contents at the end of the manual page 107 along with an index and lists of figures and tables References to other sections in the text have the Section Name page in bold IMPORTANT Important information is presented like this ignoring this may cause you to damage the unit or invalidate the warranty The manual is designed to be helpful If there are points you feel we could cover better or that we have missed out please tell us dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 USING YOUR dCS 972 FOR THE FIRST TIME Product Overview The dCS 972 DDC Digital to Digital Converter is a high performance real time sample rate and format converter It is designed for studio applications where source material is available in one format but outputs are required in other digital formats in real time For example archi
61. e the Output Frequency or any other key to cancel the attempt to turn FC mode on OnVvers1on Pure Format Conversion On Audio Input Select Sync Source Hultirle Channel Sanc Inrut Fresauency DutPrut Hode l HES Message Edit On returning to the main menu Sample Rate Conversion is shown as disabled e Rate Lonversiorn Format Conversion Error Monitor Test Into i Bit Activity Monitor Level Meters Oisrelay To re enter SRC mode you have to set Format Conversion to Off Error Monitoring Error monitoring on the input signal can be implemented for CRC parity and Valid bits in the AES3 and SPDIF message streams This menu covers resetting the monitors and is only available for PCM inputs the entry disappears for DSD inputs Test The unit can be used as a very high purity signal generator as well as performing self test functions via this menu Info This menu displays information about the unit for support purposes Bit Activity Monitors This menu turns on bit activity monitors on the selected input signal for use on the audio data it can find out how many bits you have coming in or identify stuck bits in other equipment This only works for PCM inputs the entry disappears for DSD inputs This feature does NOT monitor the units outputs dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Level Meters Controls level metering of the output data The level meters may
62. ea a 60 PIET FIR arene tata ctewecelawd wintatceoietted 60 Filter IR o ra 60 Manual for Software Version 2 3x January 2001 Filter passband ripple ccccceeeeeeeeeeeees 60 Filter phase response ccceeeeeeeeeeeeeeees 60 Filter transient response 28 60 71 Format conversion Mode 2000e0 20 21 FUSE MANS camna a a 98 99 101 FUSE YDE na 98 G Galena N 16 17 31 Generator frequency resolution 36 Generator SYNCING cccseccsseecseeeseeesaees 35 GPS SYNGCING lO aranean 10 24 Info submenu ixterteieeee cdl iateetSt Uetieweee 38 L Pee DIS Ola ctsnsece tess anmniaaciaak aE 24 VED BANCO ruorin tese ntaduamanine tees nsiieoies 15 ABT Be BD cea ene a AAA ROE 15 LED frontpaneel erer a 8 LED G la e a S 15 LED WGI CAO Mecsas nents ite Grea states seco nlaciaiadas 15 LED Noise Shaping ccccceeceeeeeeeeeeees 15 PED PINASO eena an aa 15 LED POWO poran eine aie 8 15 103 LED UMOCKE Oeria a antares 8 Level meters ccceeeeeeeeeeeees 20 22 39 40 Level meters clip indication cc06e 39 Level meters decay tiMe ccceeeeeeeees 40 Level meters DSD eee 22 39 41 Level meters nuMerical eceeeeeeeeeees 39 Level meters peak hold 39 40 41 Level meters setting the bandwidth 41 Lockout setting and unsetting
63. eeeceeeeseeeeaeeeseneeseees 86 Figure 37 44 1 kS s NOISE shaper curves c cceccceeeceeeeceeeceeeeceeeceueessueesaess 86 Figure 38 48 kS s noise shaper curves cccccccceeeceeeeceeeceeeeceeeceueesseeenaees 87 Figure 39 88 2 kS s NOISE shaper curves cccceccceeeeceeeeceeeeseeeeaeeeeaeeeseeeesaees 87 Figure 40 96 kS s NOISE shaper curves cecccceeccseeeeeeeeceeeeceeeeseeesaeeeseeeeseees 88 Figure 41 Noise shaper noise and weighted noise VS OIdel 0eceeeeeeeees 88 Figure 42 Noise Shaping and Dither Spectra cccccccccceseeceeeeeeeeeeseeeeseees 93 Figure 43 Truncation Only Spectra ccccccccccccceeccseeeseeeeceeeeseeeeseeeeseeeseeeeseees 93 Figure 44 Noise Gain and Weighted Noise Gain by Shaper Order and SIMPE RAO Renae en ee a ee Ca ea ee ce een 94 Figure 45 Changing the Mains FUSE cccccecccseceeeeeeceeeeseeeeseeeeaeeesaeeesaees 98 dCS 972 User Manual dCS Ltd Keywords and Phrases A AES Message isc ceapesderidesdewrsecasneineevacnanpent 30 74 AES Message User bits 0c008 24 25 AES X Z SUDfraMe ce cece cececeececececeeceeeseeaees 64 AES Y SUDIFGING a ee ae eee Sedat 64 PES d k aene 11 B Backlight timeout aanannannaannannannannannnennnnna 42 BalaNC E aca aa ANAA 15 16 31 Bit activity monitor ccee 20 21 38 45 DIUTOR DI aiee decent aR eters 20 Button enter cc
64. eeeeeeeeeeeseneeens 48 Figure 6 General Sample rate Conversion ccccseececeeeeeceeeeeeaeeeesaeeeeseneeens 49 Figure 7 PCM to DSD CONVEFSION c ccccceeecceeeeceeeceueeseueeceeecueeseueecueesaees 50 Figure 8 Using a Master Clock ccccccscccseecceeeecseeceuceceueecaeeeeaeeceueesueenaaes 51 Figure 9 Multi channel Sample Rate Conversion with bit aligned source 52 Figure 10 Multi channel Sample Rate Conversion with Master Clock 53 Figure 11 Multi channel Sample Rate Conversion with more alignment El SEEE S A PE EA ea A EE EE EEE E AA E E E T 54 Figure 12 Multi channel Sample Rate Conversion with multiple sample rate S OUT arna a tel aa rae a dann vase nea wise tanentacn 55 Figure 13 Transient Performance of 44 1 kS s Filter Options 0 60 Figure 14 Transient Performance of 96 kS s Filter Options eee 61 Figure 15 Word Clock and AES3 outputs 96 KS S cccccecccseceseeeneeeneeeeee 64 Figure 16 Word Clock and AES3 outputs 44 1 KS S ce cceeccc sees seen eeeeee 64 Figure 17 Word Clock in to Word Clock out 96 KS S cccecceccseeeseeeneeeeee 65 Figure 18 Word Clock in to Word Clock out 44 1 KS S cece eecee sees eeeeee 65 Figure 19 AES3 in to AES3 out 96 KS S cc ccccccceseeeseeeeeeeeeeseeesaeeneeenes 66 Figure 20 AES3 in to AES3 out 44 1 KS S 20 eecccceeeeeseseeeseeeees
65. eeesseeeeees 66 Figure 21 DSD data and Word Clock OUt cee ccceccceececeeeeseeeeseeeeaeeeseeeesaees 67 Figure 22 44 1 kS s to 96 kS s PCM showing AES3 alignment 69 Figure 23 96 kS s to 44 1 kS s PCM showing AES3 alignment 69 Figure 24 44 1 kS s to DSD showing DSD bit alignment eee 70 PIQUIG 29 Dither PDS fvcctir cecil lecenendon a ARE 80 Figure 26 Dither Spectra FF TS ccccsccccssececeseeesseecseeeceeseeseeseeseaeeeneneeens 81 Figure 27 Small Signal Raw Data with Dither ccc cecccsececeeeeeeeeeeeeeeaes 81 Figure 28 Truncated small signal FFT with and without dither 82 Figure 29 Truncated small signal FFT showing noise shaping with and WIE O UE CITING siirre a date ctastiie e eee atthe awe a 82 Figure 30 DSD output spot Q Noise for the various Filter options 83 Figure 31 DSD Output integrated Q Noise for the various Filter options 83 Figure 32 DSD Output F weighted Q Noise for the various Filter options 84 Figure 33 DSD showing 0 dBO full scale ee ecceeeeeeeeeeeeeeeeeseeeeeseeeeens 84 Figure 34 48 kS s to 44 1 kS s conversion Filter responses 06c000e 85 Figure 35 96 kS s to 44 1 kS s conversion Filter responses 0 c0000e 85 Figure 36 32 kS s NOISE shaper curves ccccceeccseceeeeeece
66. el is changed you may not be able to see the display well enough to navigate to the Display menu and increase the contrast to readable level To recover from this you can Recall a stored setup known to have a higher contrast setting see the next section If the worst happens and none are available switch off the unit then hold down the Status button while switching on The unit will display Using Default Settings and will load a setup with high contrast The third option Cursor controls the way the cursor responds to turning the encoder The default setting is the cursor moves down if the encoder is turned clockwise If you prefer the opposite arrangement move the cursor to the bottom line and press Set Clockwise Down changes to Clockwise Up Pressing Set again change back The fourth option determines the time after which the display backlight goes out The backlight is an electroluminescent device and so in theory has limited life It can also buzz a little and although we select for low buzz and acoustically damp it it can be irritating So the display goes dark after a preset period although pressing any button or turning the knob will wake it up again When the cursor is against the Backlight Off After option each time you press Set it steps through the settings min 3 min and 5 min dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Setups and Locking the Front Panel Storing
67. ells are two pass conversions where the performance depends on both conversions Input Output Sample Rate kS s 11 025 12 16 22 05 24 32 44 1 48 88 2 96 176 4 192 Rate kS s 11 025 130 122 12 139 136 16 134 134 109 132 119 130 132 121 117 105 139 47 Table 6 Typical Spurious Level vs Conversion id Spurious products For example a 1 KHz tone with a 48 kS s sample rate in will produce spurs at 2 9 kHz and 4 9 kHz 6 8 kHz and 8 8 kHz etc with a 44 1 kS s sample rate out dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Noise Noise arises from processing rounding errors and from stop band performance It is typically around 130 dBO but depends on the conversion being used Group Delay The conversion process takes time and the time is dependent on the conversion being carried out and the filters used Conversion Filter Filter Filter Filter Input Output 1 2 3 4 Sample Sample Period Period 1141 1131 1131 1131 22 676 1024 11 338 1515 1065 1065 1065 10 417 868 958 1028 948 10 417 Table 7 Group Delays PCM to PCM transitions dCS 972 User Manual dCs Ltd Clocking Internal clock Manual for Software Version 2 3x January 2001 The sample clock quality significantly determines the output performance of a DDC in as far as items connected may have to reconstitute an analogue signal and may ultimately derive their clock from the DDC clock The
68. er Manual Manual for Software Version 2 3x January 2001 dCS Ltd Multi channel Sample Rate Conversion with multiple sample rates out 48kS s Ch19 amp 20 48kS s Ch17 amp 18 48kS s FROM Ch15 amp 16 SOURCE 48kS s TO RECORDER Ch13 amp 14 44 1kS s WORDCLOCK 96kS s Chl amp 2 FROM SOURCE 96kS s Ch3 amp 4 96kS s Ch5 amp 6 96kS s Ch7 amp 8 Figure 12 Multi channel Sample Rate Conversion with multiple sample rates out dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 A dCS 992 Master Clock can also be used to sync up the source and more than one set of units all at different sample rates and be the master DVD production may require different sample rates for different channels this set up will give real time 48 kS s rear channels and 96 kS s front channels from a multi channel 44 1kS s source For all dCS 972 units set the Multi channel Sync option to On They will all set up as slaves Make sure that all the other settings are the same on each unit in a group 1 gt version 2 0 or higher software dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Manual part no DOC1241102C2 Page 5 Document No OS MA A0124 110 2C2 Contact dcs on 44 1799 531 999 email to more dcsitd co uk inside the UK replace 44 with 0 web site www dcslitd co uk dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 dCS 972 TECHNICAL INFO
69. es in 0 1dB steps When the required setting is reached press Set and the cursor will change back to W Pressing lt when the cursor is or W returns to the previous menu level Pressing Set when the cursor is W and the option cannot be adjusted e g AES in the Audio Inout Select menu selects that option and returns to the previous menu level From the Status screen pressing any of the four Operation buttons displays the last menu level used Pressing the Status button when the cursor is or E displays the Status screen for the selected menu dCS 972 User Manual dCS Ltd THE SOFTWARE MENU AND SETUPS TOP LEVEL Greyed out menu entries are not there when Format Conversion is On They prevent bit for bit operation Menu entries in italics and the menus below them may disappear if the selection of other parameters makes them unrealistic This mainly happens with DSD on Sample Rate SRC Format Audio Input Select Sync Source Multiple Channel Sync Input Frequency Output Frequency Output Mode Filter Output Word Length Noise Shaping Dither AES Message Edit SPDIF Message Edit Manual for Software Version 2 3x AES Word Clock Audio Input Internal 192 kS s 176 4 KS s 96 kS s 88 2 kS s 48 kS s 44 1 kS s 32 kS s 24 kS s 22 05 kS s 16 kS s 12 kS s 11 025 KS s Filter 1 Filter 2 Filter n Off 1st Order 10th Order Professional On Off
70. eter screen as appropriate and the front panel controls have no effect To restore normal operation hold down the Status button and press the Edit button The WSs label will disappear and normal operation will be resumed dCS 972 User Manual dCS Ltd Manual for Software Version 2 3x January 2001 TYPICAL APPLICATIONS Converting a 24 96 recording to CD format 16 bit 44 1kS s from 3 From 24bit 96kS s source independent AES outputs y AES1 AES2 AES CLK AES1 AES2 AES CLK 2 s MAINS FUSE2A T ON OFF SPDIF1 SPDIF2 SPDIF3 SYNC IN CH1 CH2 CLK HN LI I y l Q 1 Li G3 1 6 Hla DIF 2 Output 16 bit 44 1kS s 16 bit 44 1kS s from 3 SDIF 2 output independent SPDIF outputs Figure 3 Double Speed 24 96 to CD format The dCS 972 converts a double speed 96 kS s 24 bit AES input to a 44 1 kS s 16 bit signal available from all of the 3 AES 2 electrical SPDIF optical SPDIF or SDIF 2 outputs The conversion set up uses Filter 2 there is a choice of 4 The SonicStudio uses 24 96 in double speed AES at the time of writing Connect Sonic Solutions SonicStudio workstation AES output to AES 1 input on the dCS 972 Load the setup from Store or use settings below Output from either AES A or AES B or any of the SPDIF outputs or using two data cables and one clock via the SDIF 2 outputs Sample Rate Conversion settings The settings below are preloaded into Store by dCS although
71. he generator operates at the output sample rate In PCM modes it is a PCM generator in the appropriate mode in DSD mode it is a DSD generator If the unit is synced to an input when it goes into Generator mode then the generator stays sync d to that input so the output will be synchronous and locked If the unit is not sync d to anything set the Sync Source to Internal Otherwise the equipment you are trying to drive may be unable to lock to the Generator outputs because the sample rate has drifted out of lock range The Sample Rate Conversion menu is still active in Generator mode so it can enter Generator mode with no external syncing the Generator can be set up a sync input can be selected from the Sample Rate Conversion menu and the unit will sync to that Noise shaping and other features available in the Sample Rate Conversion menu can still be used as long as these operate at the output rate Filters for example do not affect the generator output because they operate on the input signal Dither operates at the output rate so it can be used Controlling the Generator 8 To view the Test Mode screen go to the top level menu select Test and press Status to get the display below assumes 96kKS s sync source Irn 9 Buses Out 44 1 k So s Waveform Generator OFF AmMelitude 15 Frequency 1 006k Hz If the unit is set to Infernal sync the screen will show Int beside the input sync source as follows
72. he list and press Set N Shaped Triangular means Noise Shaped Triangular For more information on dither and different dither types see the section Dither on page 72 and Figure 25 to Figure 28 AES Message Edit This menu sets the message bits on the AES outputs Professional On Off Non Audio On Off Mode Source Destination SPDIF Message Edit Select then press Set to toggle between On and Off Select then press Set to toggle between On and Off Select the audio data format then press Set Options are Not indicated Two channel Primary Secondary Stereophonic Select each of the four bytes in turn press Set turn the rotary control to change the character as necessary and press Set again to accept Press lt to return to the previous menu and the four characters will be displayed beside Source Set up similarly to Source This menu sets the message bits on the SPDIF outputs Professional On Off Non Audio On Off Copy Permit On Off Format Select then press Set to toggle between On and Off Select then press Set to toggle between On and Off Select then press Set to toggle between On and Off Select the audio data format then press Set Options are 2 Channel General Format Compact Disk 2 Channel Encode Decode DAT dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Gain Balance and Maximise This menu allows gain output level and balance to be set or an
73. he status screen in addition to input and output frequencies The active parameters in the list are indicated by the X sign in the box next to it For example dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 le Rate Lonversiorn Disrlasy Customise BE DRFut SiC O P Mode U Length H Share Dither indicates that the five displayed parameters are Input Sync O P Mode W Length and N Shape Dither and the options further down the list are not displayed To display a parameter that is not marked first check that no more than four parameters in the list are marked If so select the extra parameter and press Set an X sign will appear in the box next to it If five parameters are already marked select an unwanted one and press Set the X sign will disappear Then select the wanted parameter and press Set The parameters available are Input Audio input selection Sync Synchronisation source O P Mode Output mode W Length Word Length N Shape Noise Shaping characteristic applied Dither Displays Dither type used L R Flip Filter Display Filter Cut used With the top five parameters selected the Status screen might look like this Inrut AESI Sync Audio Input O P Hode Hormal W Length 24 bits H Share Off With the bottom four parameters selected the Status screen might look like this In 9 Buses eee Ott Off dCS 972 User Manual Manual for Software Version 2 3x dCS Lt
74. kS s Rotating the knob moves the arrows left and right When the arrows point to the digit that you want to edit press the Set button The knob will now increment or decrement the selected digit If you increment the digit beyond 9 then the next digit gets incremented and the current digit is set to 0 Similarly if the digit is at 0 decrementing it will change the previous digit s For example the above display shows 1kHz If we decrement the 0001 digit the result is as follows jn 1gnal PeeSne ee eee aed E W X When you have set the frequency you want move the arrows to the symbol and press Set To discard the changes and return to the tone generator menu move the arrows to the X symbol and press Set dCS 972 User Manual dCS Ltd IMPORTANT Self Test Manual for Software Version 2 3x January 2001 outputFs l If you select a frequency that is more than gt the frequency generator will outputFs automatically be set to 5 Select Generator Off and press Set it will toggle to Generator Sine Wait several seconds for the code to load up then press again and it will change to Generator Square Press again and it will return to Generator Off Press Status to display the Test Mode screen In J Bks Ot 44 1 bk 5s Waveform Generator Sine AmMelitude 12 gE Freqaquency 1 H0 k Hz The IMSA label appears on all status screens while the generator is on With the Generator On the
75. l for Software Version 2 3x dCs Ltd January 2001 fe running 1 3 90 Wediv BA lim 56 250 10 00 1 1M de 2 5 00 Vrdiv BA lim 6 000 10 00 1 Ms de 1 0000 us O 000 1 0000 us 200 ns div repetitive Trigger Mode Edge E 2 500 Figure 24 44 1 kS s to DSD showing DSD bit alignment Multiple Channel Multiple Sample Rate Synchronising DVDs can make use of mixed sample rates in their multi channel mode for example 96 kS s in the front channels and 48 kS s in the rear channels As well as the problems mentioned above in the section Multiple Channel Sync ing use of multiple channels brings an additional problem in that the group delay in the sample rate conversion process varies with the sample rate It generally gets longer as the sample rate gets lower making the rear channels seem further away than you might want Figure 12 shows how a master clock may be used with several dCS 972 s in parallel to get simultaneous synchronised sample rates out at the same time Please contact dCS if you need support for this process dCS 972 User Manual dCS Ltd Noise Shaping Manual for Software Version 2 3x January 2001 The dCS 972 uses noise shaping that is optimised to the F weighting curve It does not affect signal frequency or transient response but shapes the frequency response of errors Q noise or truncation errors so that they fall as much as possible in the less sensitive part of the spectr
76. l generate a copy based on its own timing for transmission to the next unit in the chain If the Multi channel Sync option is set to On in the Sample Rate Conversion menu any units with no user bit synchronisation data into its AES CLK Input will become a Master If user bit synchronisation information is fed in it will become a slave Either unit will output synchronisation information via its AES CLK Output A master clock dCS 992 22 can be used as the master if more than about 8 channels are being used this system is best as it avoids any tolerance build up Connections are shown in the section on Multi channel Sample Rate Conversion bit aligned sources page 52 Using the multi channel sync mode the timing of the data at the output of the dCS 972 is related to the data coming in If three dCS 972 units are used in a six channel set up and the data into all of them is bit sync d from say a six channel source the outputs will be bit sync d If the inputs are not quite bit aligned then the outputs will not quite be bit aligned If the inputs are way off in phase but frequency locked the outputs will be way off in phase but frequency locked and the timing of the block structures of the several output signals will not be defined Sample Rate kS s Time in Time in Time in input nsecs nsecs 44 1 kS s 96 kS s input Basic dCS 972 unit to unit output timing alignment Input misalignment allowed with all inputs at the s
77. later by your Distributor if necessary Specify the new voltage code Ordering Options for a New Unit To order any option check the option codes from Table 12 above and tell us dCS 972 with options lt option codes gt IMPORTANT You must specify a supply voltage option code Having Your Options Changed dCS support modifications updates and option changes to supplied units Major changes are normally carried out at dCS as we have extensive test facilities and can verify the changes Please contact your Distributor or dCS for details IMPORTANT Please do not attempt the changes yourself The unit s performance or reliability may be impaired and the warranty will be invalidated dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Manual part no DOC1241102C2 Page 97 Document No OS MA A0124 110 2C2 Contact dcs on 44 1799 531 999 email to more dcsitd co uk inside the UK replace 44 with 0 web site www dcslitd co uk dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 MAINTENANCE AND SUPPORT Hardware Service amp Maintenance dCS audio products are designed not to need regular maintenance and contain no user serviceable parts e there are no moving parts e there are no short life or wear out parts used e the units have no holes through which liquids or contamination can normally enter e no dust deposits build up to degrade performance All parts are replaceable o
78. m Store 2 or use settings below Output from either AES A or AES B or any of the SPDIF outputs or using two data cables and one clock via the SDIF 2 outputs The outputs will all be at double speed Format Conversion settings The settings below are preloaded into Store 2 by dCS although they may be overwritten Format Conversion On Audio Input Select Dual AES Sync Source Audio Input11 Input Frequency 96 kS s Output Frequency 96 kS s Output Mode Normal AES Message Edit Professional On Non Audio Off Mode Stereophonic SPDIF Message Edit Professional On Non Audio Off Copy Permit On Format 2 Ch Gen Format If using a dCS 992 Master Clock set the Sync Source to AES when using an AES Clock output or Word Clock when using a SDIF 2 output Ensure the clock signal is connected to the appropriate input on the dCS 972 dCS 972 User Manual dCS Ltd Upsampling a CD Manual for Software Version 2 3x January 2001 24 bit 96kS s Dual AES AES1 AES2 AES CLK SPDIF1 SPDIF2 SPDIF3 SYNC IN CH1 CH2 CLK SDIF 2 Output 16bit 44 1kS s AES REF WORDCLOCK IN output to 24 96 DAC AES1 AES2 AESCLK AES EBU Outputs Hand Crafted by The Red Hot CD Player Co Figure 5 Upsampling a CD to 24 96 or 24 192 The dCS 972 converts a 44 1 kS s 16 bit SPDIF input or AES3 input dotted to a Dual 96 kS s 24 bit signal available from
79. moesie ene a aE a aaa 43 Signal generator ccceccseeeeeeeeeees 35 36 37 Signal Generator DSD cccsecceeeeeeeeeees 35 Signal generator frequency resolution 36 Signal Generator PCM cccccceeeeeeeeeees 35 Manual for Software Version 2 3x January 2001 SPDIF MeSSagQ ccseeceeeeeeeeees 30 74 75 SPO en re Ce ae 61 Status SCNCOMsichs Sebcteicntios cueen badincealhsaccukencsteens 8 Store Urren Ldenomendieucoaly 8 43 44 SLOSS aaa A A A 44 Supply VOMtAGE c cece ceccceececeeeeeeeeeeseeeeeeeees 96 SVMG INK ocra 24 25 52 53 54 68 SYNC SOUCO nea i nremiebuoneieeteraaee 24 U Unlocking front panel cccececseeeeeeeeeees 45 V VCAQACCUIC V eion Gort eceeeemaen 63 VCXO Long Term Stability eee 63 VCXO Temperature Stability 00 00000000n 63 VIGO Orar iea a TE 96 W Waray orman a A 100 Warranty EXCIUSIONS cccccceeeceeeeeeeees 100 Warranty extended ceceseeeee 100 113 WIGS GING 5 Eskisi eE a 71 weighting F ccc cece eecceeeeeceeeeeeeeeees 71 72 91 Word Clock alignment cc cccceeeeeeeeeees 65 dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 x Owner Registration Transfer To transfer the balance of the Extended Warranty to a new owner please complete the form below in block capitals and forward it with the Extended Warranty Certificate to dCS
80. n re entered Fle Fate Lonversion InFut Freauency BAuWto E and the Status display will indicate that Auto is on InrFut AESI Audio DAFut O P Modes Hormal W Length 24 bits H Share Off Output Frequency Sample Rate Output Frequency is a parameter for PCM operation only Select the required Output Frequency from the list and press Set The dCS 972 accepts 96 input output frequency combinations in one pass The remaining 48 combinations can be accommodated in 2 passes These are shown in the table below OUTPUT FREQUENCY kS s 16 22 05 24 32 44 1 48 96 m 2 N gt Q Z LLI O LLI X LL A Z Table 2 One Pass and Two Pass Conversions Not all the apparently valid output frequencies may be available to you from the menu When Auto Input Frequency Selection is turned on the menu system dynamically alters the Output Frequency menu to reflect the valid 1 pass output frequencies for the current input frequency For example if Auto is turned on and the input is running at 96 kS s then the Output Frequency menu would look like this dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 If the input frequency were 32 kS s then the display would offer a different selection Onwers 1 ori Select Nalid OQubteut Freesawency 96k S s oo a kirs 4k 575 E44 Ikss 32k575 BA The input frequency can be changed to one that is incompatible with the currentl
81. n the 17th slot the Edit button has no effect Inserting lt End gt half way through a name will complete the name there deleting the lower half 0 we recommend that you store your settings in stores 4 9 Software updates will have more pre loaded setups in stores 0 3 and 10 12 and although you can overwrite 1 3 and 10 12 of these you may not wish to do so If you do be careful when installing software updates dCS 972 User Manual dCS Ltd Preloaded Setups Recalling a Setup Manual for Software Version 2 3x January 2001 If Store 4 has been named Demo the display will now look similar to this 96k gt CO Ot gt Dual 96 2Single Ursamelirng Dera EMPL EMPL EMEA Press the Enter button and a message window will appear in the display to confirm that the unit is storing the setup If you attempt to store a setup in a previously unused location without specifying a name a message window appears for two seconds stating First choose a name Units leave dCS with some stores preloaded Store QO Contains default settings and cannot be edited If you get the unit into a tangle recall this and sort things out Store Preloaded with Dual 96 kS s in as Auto to CD out 44 1 kS s 16 bits Detect Silence on Noise Shaped Triangular Dither on 2 order Noise Shaping on You can overwrite this setup store 2 Preloaded with Dual 96 kS s to double speed 96 kS s You can overwrite this setup
82. nce SPDIF Inputs Various 3 off RCA Phono BNC Toslink optical Used for SPDIF inputs SPDIF1 is the RCA SPDIF2 is the BNC SPDIF3 is the Toslink optical input Sync Input BNC This is intended for future enhancements dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Signal Outputs AES EBU Digital Outputs 3 pin XLR Male 3 off AES A AES B AES CLK Used for AES3 format signals including Dual AES mode In single AES modes AES B and AES CLK follow AES A In Dual AES modes AES A and AES B are used AES CLK is used for Sync Link operation in multi channel applications SDIF Outputs BNC 3 off CH1 CH2 Wordclock Out Used as a set for SDIF 2 PCM or DSD or CH1 CH2 used for SDIF 3 DSD only outputs SPDIF Outputs Various 3 off RCA Phono BNC Toslink optical Used for SPDIF outputs SPDIF1 is the RCA SPDIF2 is the BNC SPDIF3 is the Toslink optical output Control and Power Remote 9 pin D type Female 2 off In and Out For remote control via a PC and or downloading software updates Remote In and Out sockets allow daisy chaining of several different dCS units from one COM port Mains Supply 3 pin IEC CEE22 Switched fused and filtered IEC mains connector for 50 or 60 Hz mains Additional Information As well as connectors the rear panel displays the following information about the unit near the mains supply connector Mains Voltage The actual voltage setting supplied
83. nces to Rectangular Dither or Triangular Dither refer to the shape of the PDF of the dither dCS 972 User Manual dCS Ltd Manual for Software Version 2 3x January 2001 Straight forward dither always adds noise it can only produce signals with a noise floor higher than Q noise on its own However the noise power added is a few dBs for simple types Noise shaping adds rather more noise but it can be made to add it in parts of the spectrum that the ear is less sensitive to so the perceived noise F weighted noise is lower up to three bits lower It results in a signal that the ear hears as having a far lower noise floor than a 16 bit truncated signal rather than the not much worse of dither alone even though there is really more noise present Truncation Type with Noise Noise Comments 44 1 kS s data rate unweighted F weighted rel 16 bit Q rel 16 bit Q noise noise 31 16 bit truncation 16 bit truncation with Top Hat dither 16 bit truncation with Triangular dither 16 bit truncation with Noise Shaped Triangular dither 16 bit truncation with 2 order noise shaping and no dither 16 bit truncation with 2 order noise shaping and Noise Shaped Triangular dither 16 bit truncation with 9 order noise shaping and no dither 16 bit truncation with 9 order noise shaping and Noise Shaped Triangular dither Unpleasant low level effects Okay can show noise modulation at low signal levels
84. ncy the unit reports Samf le Rate Conversion oo Fs Out for Fs In ress Set to alter Fs In ans other key to cancel e You have selected a combination that cannot be handled in one pass see the table in the section Output Frequency Sample Rate on page 26 for valid single pass combinations Choose an intermediate frequency and convert in two passes For example if you need to convert from 32kS s to 11 025 kS s first convert to 44 1 kS s and record then convert the recording from 44 1 kS s to 11 025 kS s e While changing frequencies you have accidentally selected an intermediate combination that cannot be handled in one pass Press Set and choose a valid nout or Output Frequency as appropriate from the list The Customise Display menu will not allow another option to be set e f you check the list you should find that the maximum of 5 parameters are already marked with a X Remove one you do not need and try again dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 If You Need More Help Contact dCS Our office hours are 8 00 a m to 5 00 p m Monday to Friday UK time UTC or UTC 1hr Contact us by phone or fax on Inside the UK Outside the UK Telephone 01799 531 999 44 1799 531 999 Fax 01799 531 681 44 1799 531 681 Table 13 dCS Phone Numbers You can write to us at dCs Ltd Mull House Great Chesterford Court Great Chesterford Saffron Walden CB10 1PF UK Our E Mail addre
85. nd Dither Only Comparison dCS 972 SW v1 54 60 16 bit truncation Noise Shaped Triangular dither 16 bit truncation Top Hat dither 80 16 bit truncation 10th order noise shaping Noise Shaped Triangular dither PER 16 bit truncation 10th order noise shaping no dither P E a ee a Oe a Paa 100 u w ae m i Pa oO kd ad yt m o Ce AF POP agp fig Fe ee Pe ye OR a E k oo annu A A Ai e REE ENS aa ONT a M 120 paige ss EON IN HO x UT ease i lt x io pn l re wane Fi AN gt r oe m AR jo 140 fe Foals Ne ett a 160 0 2 4 6 8 10 12 14 16 18 20 22 Frequency kHz Figure 42 Noise Shaping and Dither Spectra Spectra of 90dB 24 bit sinewave truncated to 16 bits with dither options dCS 972 SW v1 54 60 __ 24 bit source data 80 TT 16 bit truncation no dither 89 70 dB 16 bit truncated it 91 00 dB source signal m B f 2 pi F z f Sg e g T 5 z i 1207 cc 2 Q g E a aF E E TE sa Li f T E j i E3 3 fa i ay an r F rh 1 w A i he R r i i ip 5 i 4 j f 7 wear i oe ty t ar Pe i r 7 p p aai bafer wy e k Fu z p 140 e OS Ei oa T ka F TS i i y hae t er a ef t T og w w r F y os i pe p a 4 1 A 1 N r i i ay w t 1 x y N I i aot ns E a 160 Aa E k AA i f ao A ii A A N l Mall n Ane a i 12 14 0 2 4 6 8 10 16 18 20 22 Frequency k
86. nobs below navigate you through it OPERATION buttons The bank of 4 buttons in the top left hand corner are the Operation buttons and are used for navigating around the menu tree Status returns the display to the status information screen to allow a rapid check of key settings i selects the previous higher menu level gt selects the next lower menu level Set implements the selected menu item MEMORY buttons The bank of 4 buttons in the lower left hand corner are the Memory buttons and are used for storing and retrieving setups Recall allows one of ten stored setups to be selected ready for loading Store allows one of ten locations to be selected as the location for saving the current setup Edit is used to change the name of a saved setup Enter loads or saves a setup LCD display The backlit LCD display in the centre of the panel can display up to 8 lines of information dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 LED indicators A group of LED indicators to the right of the LCD display gives a level of status indication Dither is lit if any Dither is selected Noise shaping is lit if any Noise Shaping is selected L R flip indicates that the channels are flipped Two Phase LEDs indicate if either or both channels are phase inverted Gain is lit if the setting is other than unity gain i e OdB Balance is lit if the channel balance is shifted from centre Unlocked is lit if the unit is
87. oftware Version 2 3x January 2001 Bit Activity Monitor Submenu 38 Bit Activity Monitoring Overview 38 Setting the Monitor 38 Level Meters Submenu 39 Level Meter Overview 39 Turning the Level Meters On 39 Meter Type Bar or Numerical 40 Decay Time 40 Peak Hold 40 Using the dCS 972 to monitor a track 41 Watch Out for this One 41 Display Submenu 42 Setups and Locking the Front Panel 43 Storing a Setup 43 Preloaded Setups 44 Recalling a Setup 44 Locking Out Changes and Unlocking Again 45 Typical Applications c eiia reer dea cavesaan a aaa aaaea Eaa 46 Converting a 24 96 recording to CD format 46 Demultiplexing a 24 96 Dual AES recording Bit for Bit 47 Upsampling a CD 48 General Sample Rate Conversion and Distribution 49 PCM to DSD 50 Using a Master Clock 51 Multi channel Sample Rate Conversion bit aligned sources 52 Multi channel Sample Rate Conversion Using a Master Clock 53 Multi channel Sample Rate Conversion with more alignment tolerance 54 Multi channel Sample Rate Conversion with multiple sample rates out 55 dCS 972 Technical INfoOrmation ccccccecceeseeeeeeeeeeneeeneseneseneseeeeeeeeeneseneaaaes 58 DSD 58 PCM input and or Output Performance 60 Clocking 63 Sample Alignment 64 Multiple Channel Sync ing 68 Multiple Channel Multiple Sample Rate Synchronising 70 Noise Shaping 71 Dither 72 Digital Interface Specifications 73 Message Handling 74 AES EBU Message Handling 74 SPDIF Message Handling 15
88. onitor Submenu 38 Level Meters Submenu 39 Display Submenu 42 Setups and Locking the Front Panel 43 FY DICAIAD DIICAIONS iciae webs tense ot vecnsdadwendus siethevsacavdeaucuwuast 46 Converting a 24 96 recording to CD format 46 Demultiplexing a 24 96 Dual AES recording Bit for Bit 47 Upsampling a CD 48 General Sample Rate Conversion and Distribution 49 PCM to DSD 50 Using a Master Clock 51 Multi channel Sample Rate Conversion bit aligned sources 52 Multi channel Sample Rate Conversion Using a Master Clock 53 Multi channel Sample Rate Conversion with more alignment tolerance 54 Multi channel Sample Rate Conversion with multiple sample rates out 55 dCS 972 Technical INformation ccccceeceeeeeeeeeeeeeeneeeneeeneseneseeseeeeeeneeenenaaes 58 DSD 58 PCM input and or Output Performance 60 Clocking 63 Sample Alignment 64 Multiple Channel Sync ing 68 Multiple Channel Multiple Sample Rate Synchronising 70 Noise Shaping 71 Dither 72 Digital Interface Specifications 73 Message Handling 74 Power Consumption 77 Size Weight and Operating Conditions 78 d S 972 PerlormanCe GuUive wicciiee ieee E nee eli 80 General Technical INformation cccccsccesseeeeeeeeeeeeeseneeceesanenenesenesenesenesens 90 Word Length Reduction 90 PU ONS aeo EEE A 96 Locking to Video Sample Rates 96 Mains Supply Voltage 96 Ordering Options for a New Unit 96 Having Your Options Changed 96 dCS 972 User Manual Manual for Softwar
89. ore dcsltd co uk Remove Fit MAINS FUSE 2A T ON OFF old fuse new fuse Cie before removing cover MEY 50 coHz Disconnect mains Figure 45 Changing the Mains Fuse IMPORTANT Disconnect from the mains before changing the fuse dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Software Installing New Software There are two major components of software in your unit These are the operating software and the display software The operating software can be downloaded via the RS 232 link from a PC COM port using the Windows Remote software running on the PC To use this follow the installation instructions on the floppy discs the remote software is supplied on Then run the remote programme with whatever units you want connected The software will scan the RS 232 chain for units this takes a while to see what is connected It then reports back and for each there is an info button This gives you the option of installing new software in that unit The display software comes in an EPROM which has to be manually installed The top cover has to be removed the old EPROM on the front panel board removed from its socket 1 4 of the way from the right hand edge looking at the unit from the rear and the new one installed Make sure it is installed the right way round IMPORTANT Disconnect from the mains before removing any covers or changing the fuse dCS 972 User Manual dCS Ltd Warranty
90. ou have a lot of gain to max up At the start of the track select Maximise then Reset max hold and press Set At the end of the track select Maximise then Maximise and press Set The gain correction will be applied Replay the track and the gain will be Maximised Select Maximise then Disolay max hold and press Set to see the current peak signal record Swap channels Fle Rate Lonversiorn Suar Channels BHormal Suwarred This allows the left and right channels to be swapped For normal operation select Normal and press Set To swap channels select Swapped and press Set the L R Flip LED will light up The dCS 972 has a global gain of 0 01 dB absolute so when the unit says O dB the overall gain will be 0 01 dB This is because noise shaping dither and a few other mechanisms can add small amounts to an input signal but enough to cause digital clipping The 0 01 dB global gain shift avoids the problem dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Phase The options for Phase are Normal Select then press Set Outputs are in phase with inputs Both Phase LEDs are off Left Inverted Select then press Set Left channel is out of phase with input Right is in phase Left Phase LED lights Right Inverted Select then press Set Right channel is out of phase with input Left is in phase Right Phase LED lights Both Inverted Select then press Set Both channel outputs are out of phase
91. ourage you to experiment with the filters to find the one that sounds best for your particular application Do not assume that one filter is best for all applications The menu is dynamic that is it updates to show valid selections For example Fs In 96kHz Fs Out 44 1kHz has 4 options and shows onVvers lor cut 1 cut cut 3 cut 4 While Fs In 96kKHz Fs Out 88 2kKHz has only one option and shows The reports we receive from users suggest that for PCM work Filter 2 is well suited to some classical music and that Filters 3 and sometimes 4 suit rock However views vary quite a lot dCS 972 User Manual dCS Ltd Output Word Length IMPORTANT Noise Shaping 6 Manual for Software Version 2 3x January 2001 Ones Lor BFilter cut 1 The dCS 972 remembers the last filter selection for every conversion so if you choose Filter 4 for 9644 1 and Filter 2 for 9648 these separate settings will be stored and loaded when you switch between them Select the required Word Length from the list and press Set The dCS 972 generates long word length 24 bit data and truncating this adds extra noise It can also add highly undesirable behaviour at low signal levels We recommend that you use a high order noise shaping function but see the section Word Length Reduction page 90 and try for yourself This is a seriously major topic and you should experiment Noise Shaping is a technique in which the noise energ
92. ple Rate Conversion menu set the cursor adjacent to Sample Rate Conversion and press the button The screen will change to Sy Raudio Tae ae Select Src SOME Multirle Channel Syrc TheEWt Fresawencs Oubeut Freeswerncy OWE Mode Filter The cursor shape is still because the option selected has a lower level The symbol in the lower right hand corner indicates that there are more options available than can be displayed Use the rotary control to move the cursor down the list When the bottom is reached the list will scroll upwards and a T appear in the upper right hand corner to indicate that there are more options above When the bottom of the list is reached the symbol disappears The screen displays Onvers lor P EEDIF he a Edit Gain Balance Suware Channels Phase Detect Silence De Pre EmrPhasis BOisrelay Customise Move the cursor back up to Balance Gain and press the button to display the bottom level OnWwers Lor Gain Balance BGsin 6 Age Bal L d F AdE Haximize dCS 972 User Manual dCs Ltd Manual for Software Version 2 3x January 2001 The cursor has changed to W to indicate that the bottom level has been reached Turning the rotary control will move the cursor up and down the list Now press the Set button to accept Gain and the cursor changes to to indicate that this parameter Gain may now be adjusted using the rotary control Turn the control either way and the Gain chang
93. r the 0 20 kHz band is a good target it does not match the ears response that well The F weighted curve is currently accepted as a good model for the ear and we can use this to weight the noise produced by the various filter choices Such a weighting is shown in Figure 32 on page 84 and DSD gives very good performance using such a weighting better than 23 bit pcm The figure shows that Filter 6 and 7 give more F weighted Q noise suppression in the audio band than Filters 1 to 5 Filter 6 gives around 20 dB more suppression than Filters 1 to 5 under all circumstances and Filter 7 gives 20 dB more suppression below 10 kHz dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 SACD specifies ultrasonic noise in two bands These are specs informative specs E2 and E3 and filter performance for a number of specs including these are given below The measurements given have been made using a Fourier Transform based method Filter Comments SQNR SQNR E2 spec E3 spec 20 kHz F weighted dB dB dB dB High SQNR 126 14 136 56 high stability High SQNR 127 23 138 76 High SQNR 124 66 134 38 very high stability Extremely high 122 07 129 91 stability Reduced 100k 122 27 130 14 noise Single 110 78 151 02 complex zero Real zeros 101 5 132 41 SACD Spec Table 5 DSD Filter Performance DSD Data Formats DSD is supported on SDIF 2 and SDIF 3 formats i Super Audio CD System Specifications Part 2 Audio
94. r upgradeable by dCS for a period of at least five years from the date you purchased your unit If your unit is damaged in some way please contact your Distributor or dCs User Changeable Parts There are no user serviceable parts inside the case Routine maintenance is not necessary and repairs are generally carried out by dCS since this allows us to thoroughly verify the results before shipment There is a mains fuse in the mains socket accessible from the outside of the unit This may be changed by the user The current consumption of the unit is very low 150 mA at 110 V so it only blows if there is a fault usually if the unit is set to its low voltage setting 100 120V but has been plugged into a high voltage mains 220 240V Usually no other damage is caused but if the fuse blows repeatedly on replacement some other damage will have been done and the unit must be returned to dCs for repair Fuse Type 20 x 5mm 2 amp HRC fuse If the fuse should fail it is essential that it be replaced with one of the same type Failure to do so could result in damage to the unit and may invalidate the guarantee To gain access to the fuse remove the IEC mains connector use a small flat bladed screwdriver to pry up the tab on the fuse carrier and pull it out Push the fuse out of the clip in the carrier and replace it with a new one Push the carrier back into the unit so that it clicks home See base for serial number dCS 972 m
95. rongly discouraged The SDIF 2 message is given in the table following The dCS 972 implementation sets all bits of the User message to 0 DESCRIPTION Definition Default Message Undefined 0000 Oxxx 0000 Oxxx Emphasis No emphasis Xxxx X00Xx Xxxx X00x Emphasis 15usec 50usec XXXX X01X Dubbing Prohibit Dubbing allowed XXXX XXXO XXXX XXX0 Dubbing inhibited XXXX XXX1 Block Code Start of block XXXX XXXX 1 as required Not start of block XXXX XXXX Q as required Table 10 SDIF 2 Message Table SDIF 3 Message Handling At present no messaging is implemented in SDIF 3 dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Power Consumption The dCS 972 has a linear power supply and so power consumption changes as the mains voltage changes The internal regulation is comparatively efficient for a linear supply so these changes are kept to a minimum Consumption is independent of mains voltage selector switch setting Power Consumption with Mains Voltage measured as AC power into mains socket Nominal mains 16 W Mains 10 14 W Mains 10 19 W The actual intended supply voltages are shown on the rear panel 50 Hz or 60 Hz operation is not important the unit can use either In general users will not need to change the mains input configuration If you do need this to be done please see the section Having Your Options Changed page 96 in this manual and contact your distributor or dCs
96. s summarised below Sample Rate kS s Noise Added Noise Perceived Power Power Noise 0 Fs 2 unweighted Added F weighted No dither straight truncation Top Hat dither Triangular dither Noise Shaped Triangular dither Table 9 Noise Added by Dither Types If dither is used it is shaped made less audible by noise shaping This applies as much to noise shaped triangular as the others dCS 972 User Manual dCS Ltd Digital Interface Specifications AES EBU AES3 Type Impedance Sensitivity unloaded Maximum Wordlength Damage level Connector Connections SDIF and DSD Type Impedance Sensitivity unloaded Maximum Wordlength Damage level Time skew Wordclock in out Connector Connections SPDIF electrical Type Impedance Sensitivity unloaded Maximum Wordlength Damage level Connector SPDIF optical Type Maximum Wordlength Wavelength Connector IMPORTANT Manual for Software Version 2 3x January 2001 Output Balanced differential 110 110 1 10 gt 6 24 24 gt 50 XLR3 female XLR3 male Ground or shield Signal Signal Output Single ended ground referred 100 lt 25 TTL TTL 24 24 gt 10 lt 100 BNC x 3 BNC x 3 CH1 left CH2 right Wordclock Output Single ended ground referred 15 15 0 5 1 0 24 24 gt 10 RCA Phono amp BNC Output Optical 24 24 660nm Toslink EIAJ CP 340 The Toslink interface is not specified for operation at 88 2 or
97. se Level Meters To access the monitor return to the top level menu select Bit Activity Monitor and press Set or Status With a substantial 20 bit input signal the display will be similar to this Bit Activity Monitor i LSE LS k k RS ET tE CEs EET EES FES PET EE E eaaa 23 15 T A The display is updated approximately three times per second The Display Timeout function is disabled while the Bit Activity Monitor is being used dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Level Meters Submenu Level Meter Overview The Level Meters monitor the Left and Right output signal levels They work on all PCM signals and can be used to monitor DSD by setting a DSD to PCM conversion The dCS 972 can be used purely as a programmable meter Because the meters work on the output data the filters can be used to change the bandwidth of the meters For example they can be used to monitor 96kS s data with a 20kHz bandwidth by setting the output rate to 44 1kS s or the full bandwidth can be examined by setting the output rate to 96kS s The Display Timeout function is disabled while the Leve Meters are being used Turning the Level Meters On To access the Meters return to the top level menu select Level Meters and press Set or Status With an input signal applied the display will look similar to this In 32 uses Ot 44 1 kb 5s lt a ee db co 2h 21 i 5 a a 6 A G
98. ss more dcsltd co uk Our web site is http www dcsltd co uk Other Information dCS produce technical notes from time to time If you are interested in these please do not hesitate to contact us dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 INDEXES AND SOFTWARE VERSION NUMBERS This manual is for software version 2 3x v2 3x versions differ only in a few minor bug fixes v2 3x much enhanced DSD modulator options and SDIF 3 for DSD v2 2x multi channel syncing facilities change in the level drop from 0 1dB to 0 01dB in sample rate conversion mode enhanced level metering facilities and operation of the RS 232 interface to give lid on software updating V1 54 major update Definitions of Units dBo Level in decibels referred to a full scale sine wave in a sampled system So 0 dBO is full scale dBOpsp Level in decibels referred to the defined full scale sine wave in a DSD system So 0 dBOpsp is the zero dB audio reference level dBu Level in decibels referred to a 0 775V rms sine wave with no external loading u unloaded The level of 0 775V is derived from the older dBm for which the reference level is 1mW of signal power into a 600Q termination from an output with 6002 source impedance dBV Level in decibels referred to a 1 0V rms sine wave with no external loading kS s Sample rate in kilo samples per second This replaces kHz which is technically incorrect when
99. tion country The voltage is not intended to be changed by the user If it needs to be changed see the section Having Your Options Changed on page 96 free if we email them and you download from a PC COM port Low cost if you ask us for EPROMs or other media we charge for media and handling dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Installing Unit in a Rack The unit is supplied with 19 rack mount ears fitted If it is to be installed in a 19 rack the ears supplied may be used to locate it in the rack but IMPORTANT The ears should not be used as the only mechanical support The unit should rest on a Shelf or be supported in some other way The ears will just locate it in the rack and stop it sliding forwards If the unit is not to be rack mounted the ears may be removed dCS 972 User Manual dCS Ltd Getting Started Manual for Software Version 2 3x January 2001 Here s what to do If the unit does not behave the first time you power up contact your dealer or dCs Check the appropriate mains supply for your local mains is marked on the rear panel If it is using the lead supplied connect the unit to the mains connect no other leads at this stage and switch on The Power LED will light then the screen will light up and display rece wit COT Data Conversion Systems After approximately 15 seconds the front panel LEDs will indicate the last stored state an
100. tion in the final signal although the quite high level of total noise power now present means that the process should be carried out after major editing There is another option not supported by the dCS 972 generate the dither independently of the signal and frequency shape it prior to addition but do not add it in an error shaping loop This seems to dCS to combine the worst of all worlds the high noise floor in the 0 6 kHz area of straight dither and the high total noise of noise shaping However some people use it What does it look like Figure 42 gives the spectra of 16 bit truncated 44 1 kS s signals with a 90dBO sine present for two dither only signals Top Hat Noise Shaped Triangular a 10 order noise shaped signal and a 10 order noise shaped signal with added Noise Shaped Triangular dither The equivalent simply truncated spectrum is shown in Figure 43 separately because it is so revolting In it we can see that at the signal level shown 90dBO error power from the quantising truncation is beginning to pile into the fundamental which is showing an amplitude error of 1 3 dB This would show up on a conventional linearity plot although the sign of the error could be either way 33 for example from synthesisers for comparison with the table 10 and 9 order noise shaping are very similar dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Noise Shaper Noise Shaper with Dither a
101. to sync to the dC 972 and not to a Master Clock e Ensure the destination device is capable of locking to the selected Output Frequency e Check for damaged cables The destination device locks but no signal or noise is received e Display the Level Meters to ensure signal is present on the outputs e Check that the est Generator is off by pressing the Status button e Ensure the destination device is set to sync to the dCS972 and not to a Master Clock The destination device connected to the AES or SPDIF outputs reports an error e Check that AES and SPDIF Messages are correctly set up e Check for damaged cables e Check that the destination device can receive the sample rate the dCS 972 is putting out in the appropriate 1 wire 2 wire format Output audio quality is poor e Check that Output Wordiengih is set correctly e f truncating from 24 bits use Noise Shaping and or Dither e Ensure the unit is locked to the source device or an external clock driving the source device e Converting from a very low sampling frequency to a high sampling frequency cannot give sparkling hi fi performance although it can improve things a bit the upsampling phenomenon The dCS 972 can convert a 12 kS s 8 bit signal up to 96 kS s 24 bit in real time but the linearity will be poor due to lack of source information the noise floor will be high and the audio bandwidth will still be 5kHz i e not much better than a telephone line
102. ts are active when the dCS 972 is locked They may all be connected to external equipment simultaneously if required Similarly all of the inputs may be connected as the active one will be selected by the Audio Input Select menu Now you will need to familiarise yourself with how the control software and menu system work Read the short section on Navigating through the Menu what the On Screen symbols mean page 16 so you know how the buttons and cursor work You may also find it convenient to refer to the Quick Start Guide while you are getting to know the unit dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 THE HARDWARE CONTROLS AND CONNECTORS Rear Panel AES1 AES2 AES CLK SPDIF1 SPDIF2 SPDIF3 SYNC IN SDIF 2 Output Figure 1 Rear Panel All input and output connectors are mounted on the rear panel Individual connectors are clearly identified by the panel legend Viewed from the rear from left to right and top row first the connectors are as follows Signal Inputs AES EBU Digital Inputs 3 pin XLR Female 3 off AES 1 AES 2 AES CLK Used for AES3 format signals AES 2 is used in Dual AES mode while AES CLK is used for AES3 references and also for Sync Link operation in multi channel synchronising SDIF Inputs BNC 3 off CH1 CH2 Wordclock In Used as a set for SDIF 2 PCM or DSD or CH1 CH2 used for SDIF 3 DSD only Wordclock In may also be used for a 10 MHz GPS refere
103. ttom section Manual for Software Version 2 3x 96kS s Noise Shape Plot dCS 972 SW v1 54 3rd or 7th Order Recommended 12 16 20 24 28 32 36 40 Frequency kHz Figure 40 96 kS s noise shaper curves Weighted Noise Improvement vs Shaper Order dCS 972 SW v1 54 _ 44 1 kS s Mar ds ea Ai iao Noise Shaper Order January 2001 Order 1 Order 2 gt Order 3 _ Order 4 Order 5 Order 6 o Order 7 Order 8 Order 9 Order 10 44 48 Figure 41 Noise shaper noise and weighted noise vs order dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 Manual part no DOC1241102C2 Page 89 Document No OS MA A0124 110 2C2 Contact dcs on 44 1799 531 999 email to more dcsitd co uk inside the UK replace 44 with 0 web site www dcsltd co uk dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 GENERAL TECHNICAL INFORMATION Word Length Reduction Word length reduction truncation causes an error signal to be added to the wanted signal The error signal is usually referred to as Q noise or Quantisation noise the approximation is made that the errors are noise like This is true for large signals but for smaller ones it is not so As the wanted signal gets smaller the complexity of the error signal decreases and the errors first of all pile into ever lower order harmonics or intermods an
104. um The architecture used also shapes dither where this is added For all the major sample rates 32 kS s 44 1 kS s 48 kS s 88 2 kS s 96 kS s the noise shapers have been individually optimised and the first 10 orders are offered The 1 3 and 9 shapes for 44 1 kS s agree well with Wannamaker s published results Noise Shaping adds more noise power but because of the shaping it is perceived as lower noise There is a compromise to be drawn as more aggressive shaping is used more noise is added and less perceived improvement occurs In practice things stop improving by about the 10 order The increased real noise power can cause small clicks in editing if this is carried out after the shaping For each major sample rate we recommend an aggressive and a gentle setting below Highest Order Gentle Shaping Lowest Order Sample Rate kS s 32 44 1 48 88 2 96 Aggressive Shaping Table 8 Noise Shape Orders by Output Sample Rate The gentle shaping tends to follow the E weighting curve by chance For more information on this topic either see Word Length Reduction on page 90 or read the references below it actually uses an Error Shaping architecture but the name is now being used for entirely other things and is less well known so we call it erroneously Noise Shaping j Minimally Audible Noise Shaping S P Lipshitz and R A Wannamaker J AES vol 39 no 11 p836 852 Psychacousticall
105. um mas imum average Edge Yavg CZ 3not found 0 00000 Y 0 0000D O 0g0000 W 1 150 0 mY Figure 13 Transient Performance of 44 1 kS s Filter Options Use of higher sample rates gives much tighter transient response with much less energy smeared into the pre and post ringing The transient responses of the 96 kS s output filters are shown below Filters always have some ripple For zero ripple filters this is in the udB to pdB region For conversions where the lowest rate used is 16 kS s 22 05 kS s or 24 kS s some conversions cut off at 33 of the lowest sample rate dCS 972 User Manual Manual for Software Version 2 3x dCS Ltd January 2001 AS running 1 2 00 Vedi pos 1 000 Y 10 00 1 Ms de m 2 00 Vedi m 2 00 Wrdiv ms 2 00 W div md 2 00 Vedi 550 00 us 50 00 us 450 00 us 479 EP 100 usdi repetitive Trigger Mode current minimum mas imum average Edge Yavg inot found O 00000 Y O o0000 O 0g0000 W q 150 0 m Figure 14 Transient Performance of 96 kS s Filter Options Spurs Sample rate conversion is a linear process so spurs are not caused by mechanisms that produce harmonic distortion Spurs are caused by high order images of the baseband input signal aliasing back into the output The filtering in the converter has to suppress these We measure these spurs for a 1 kHz input signal typical values are given in dBO for a 1 dBO sine wave in the table below The blank c
106. v repetitive Trigger Mode Edge 1 f 2 250 Figure 17 Word Clock in to Word Clock out 96 kS s fo running 1 2 90 diw BA lim 2 500 1 000 1 1Mse de 2 2 00 Vrdi pos 7 000 1 000 7 30s de 2 5000 us O 000 2 J000 Us 3090 ns div repetitive Trigger Mode Edge 1 2 250 Figure 18 Word Clock in to Word Clock out 44 1 kS s If tighter alignment of Word Clock In to Word Clock Out is needed consider using a dCS 992 Master Clock where the phase of individual word clock feeds is adjustable or contact us 2 if this misalignment causes you a problem please contact us dCS 972 User Manual dCS Ltd Manual for Software Version 2 3x January 2001 AES3 in and out are related as below where they are at the same sample rate and the AES3 input is used as a sync source The alignment is better than 40 nsecs Input is at the top of the displays output is at the bottom Signals are at the sockets on the dCS 972 fe running 1 2 00 div BA lim 4 500 w 10 00 1 IAs de si Eoi PEE E E E Alin ote Poros omo oe oom ob a age e e ge e e a L 1 ls E E E aA Zo 2 00 Vediy pos 4 000 10 00 1 Ms de ee Bm a 1 0000 us O 000 s 1 0000 us 200 ns div repetitive Trigger Mode Edge E f 2 496 Figure 19 AES3 in to AES3 out 96 kS s fe running 1 2 00 Vedi PERT BH lim 4 500 V digi an Fie a a ete ra a aac A pomy Fo oS ao oe
107. ves might be made for storage in 24 192 or 24 176 4 formats and then used to produce output in SACD DVD CD and other multimedia formats AES3 SPDIF SDIF 2 and DSD formats are all supported and multiple units may be synchronised for stable multi channel operation The unit is mains powered and is housed in a 2U 3 5 high 19 rack mounting case It may be controlled either from its front panel or from a software based remote control running on a PC Frequently used Setups may be stored and re called later The last setting is automatically stored on power down so that fixed installations may be set up at leisure installed and then left alone Unauthorised alterations to settings may be prevented by a panel lock out feature Numerous monitoring functions are provided both for the audio signal and for messaging attached to it The unit has bit activity and level meters and message manipulation CRC parity and invalid errors may be monitored and reported so that right first time transfer to disc plants may easily be achieved The unit is highly software based and more functions and features are added from time to time Software updates from dCS are free What s in the Box The contents of the box are at least dCS 972 User Manual Quick Start Guide Mains Lead 2 Spare Fuses Remote cable Remote software Mains Voltages The dCS 972 is shipped with its mains voltage preset for operation in the destina
108. will be cleaned If you need to synchronise several items of digital equipment we recommend using a dCS 992 Master Clock dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Sample Alignment The dCS 972 aligns samples such that Word Clock Out aligns with AES3 samples out the rising edge of word clock aligning with the start of the first illegal code in the X Z subframe preamble and the falling edge aligning with the start of the Y subframe preamble AS running 1 2 00 div BA lim 2 500 1 000 1 308 de 2 2 00 VWrdiv BA lim 4 000 10 00 1 1M de 1 0000 us 0 000 s 1 0000 us 200 ns div repetitive Trigger Mode Edge 1 2 250 Figure 15 Word Clock and AES3 outputs 96 kS s fe running 1 2 90 diw BA lim 2 500 1 000 1 30s de 2 2 00 Wrdiv BA lim 4 000 10 00 1 Ms de 2 5000 us O 000 2 2000 Us 3090 ns div repetitive Trigger Mode Edge 1 f 2 250 Figure 16 Word Clock and AES3 outputs 44 1 kS s dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 When Word Clock In is used as a sync source in and out are related as below The lower waveform is the output the upper one is the input For 44 1 kS s out leads in by about 500 nsecs and for 96 kS s it is about 230 nsecs Se running 1 2 90 diw BA lim 2 500 1 000 17 1M de 2 2 00 Vrdi pos 27 000 1 000 7 30s de 1 0000 us O 000 g 1 0000 us 200 ns di
109. with inputs Both Phase LEDs light Detect Silence Detect Silence is a PCM only option that gives digital silence out if the unit detects digital silence in This is useful where dither and or noise shaped truncation are being used without it even if the signal in goes to digital silence the output will continue to output low level noise It allows some automation further along the CD preparation chain The options are On Select then press Set Output goes silent after about 25 msecs of silence in Output recovers immediately when the input goes live although it takes about 25 msecs for the dither to turn back on if this is used Off Select then press Set IMPORTANT Digital Silence detection does not currently operate in DSD De Pre Emphasis Emphasis may be applied or removed using this menu The menu displays ample Fa De Pre mene ie Bott De Emehasis Sb 1 SuSec De EmePhasistClCITT J 1lr Pre Enehasis 567 1Susec Pre Emphasis CCITT J i Select the appropriate function and press Set IMPORTANT Note that unit drops the signal level by 12 dB when applying pre emphasis to prevent overloads occurring When removing pre emphasis de emphasising there is no signal drop When units are run back to back therefore in any order applying and removing pre emphasis there will always be a 12 dB signal drop Display Customise This menu allows the user to determine which five parameters are displayed on t
110. y Optimal Noise Shaping R A Wannamaker J AES vol 40 no 7 8 p611 620 dCS 972 User Manual dCS Ltd Dither Manual for Software Version 2 3x January 2001 The dCS 972 uses relatively unusual dither generators to achieve the very good statistics necessary for audio purposes Many dither generators use PRBS generators Pseudo Random Binary Shift register generators These are well known well documented and very predictable but unfortunately their statistics are not that great The problem shows up as a spectrum that is not flat and histograms PDFs Probability Density Functions that diverge from the ideal quite significantly Adding dither adds noise Top hat dither uses one generator per channel to add 0 5 Isbs p p of rectangularly distributed dither and triangular dither uses two generators per channel to add 1 Isbs p p of triangularly distributed dither This is on top of the Q V12 rms dither from word length reduction in the first place where Q is the size of the output word Isb The noise shaped triangular setting uses one generator to add 1 Isbs p p of triangularly distributed dither that is frequency shaped and so has low perceived weighted noise power This last is a Significant test of generator performance the dCS 972 performs very well Performance curves for all these settings including PDFs of the added dither are given in the dCS 972 Performance Curves page 80 The noise added by the dither settings i
111. y added by truncating a longer word is pushed into the less audible parts of the spectrum giving a useful improvement in perceived noise level There is a trade off between noise floor improvements in the mid band where the ear is most sensitive and increased noise at the top of the audio band which the ear does not hear but your system might Noise Shaping is achieved by processing the truncated bits so it is not available if the output word length is the same as the input word length Dither is different and additional to Noise Shaping and is necessary under some circumstances dCS consider Dither to be unnecessary in many situations Noise Shaping alone is sufficient and lower noise See the section Word Length Reduction page 90 for more information Entering the menu shows aMPle Rate Lonversion Hoise Sharing Bott lst Order nd Order arg Order 4th Order oth Order Select the required Noise Shaping characteristic from the list and press Set The options are up to 10 order for sample rates up to 96kS s Noise Shaping is not applicable to DSD For 32 kS s 44 1 kS s 48 kS s 88 2 kS s and 96 kS s the curves are individually optimised If you need curves optimised at other sample rates contact us dCS 972 User Manual dCS Ltd Dither Manual for Software Version 2 3x January 2001 Entering the Dither submenu shows Triangular or Hs H Shared Triangular Select the required Dither characteristic from t
112. y an authorised dCs Distributor e the product is operated in a system without a mains earth or ground connection e the unit is returned inadequately packed If you experience problems with your dCS 972 you should check the Troubleshooting section on page 102 You may be able to resolve the situation yourself for example by changing a menu setting If this does not resolve the problem contact your local authorised dCs Distributor for advice quoting the model the serial number from the underside of the unit the software version number see the Info Submenu page 38 and giving a detailed description of the fault Please do not return any unit to dCS without obtaining a Service Return number as this will delay the repair You may also incur costs if the unit is found to have no fault When returning a unit the original packing should be used to avoid transit damage Replacement packaging sets may be purchased from dCs During the Warranty period there will be no charge for repair or replacement dCS 972 User Manual Manual for Software Version 2 3x dCs Ltd January 2001 Update or Calibration You may wish to have your unit updated occasionally dCS offer this service we will install any modifications or updates that have occurred since your unit was first shipped and give the unit a full retest to current standards The price will depend on the hardware changes necessary so contact your dealer or us In order to ensure spee
113. y selected Output Frequency because it needs a 2 pass operation As an example we might have 11 025 kS s coming in not on Auto and try and select 96 kS s The dCS 972 will detect that this ought to be a 2 pass operation and display the following information box 441 A 5 CECE i Invalid Fs In for Fs Out Press a key to alter Fs Out 1 Bali L BdB RF Bde While displaying this information box the output of the dCS 972 will be muted To continue either Change the input frequency to one suitable for conversion see the table above or Press any key and the dCS 972 will display a list of valid Output Frequencies as follows for our 11 025 kS s example For 2 Pass conversion convert the input to an intermediate frequency and either feed it direct into another dCS 972 or record the result then convert from the intermediate frequency to the required frequency You can always choose one of 44 1 kS s or 48 kS s as the intermediate frequency so you can record the intermediate pass on most recording devices However it is best to use the highest possible sample rate for the intermediate pass if your recording device can take it For example to convert from 192 kS s to 12 kS s first convert from 192 kS s to 96 kS s and then convert from 96 kS s to 12 kS s Use of two dCs 972 s avoids intermediate storage dCS 972 User Manual dCS Ltd Output Mode Filter Manual for Software Version 2 3x January 2001 For DSD output

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