K40 CW Decoder Guide
Contents
1. K1EL CW Decoder Board Kit K 40CW Introduction K40CW is an accessory board for the K40 CW Keyboard that allows the K40 to decode and display CW The K40CW board accepts audio from a receiver and then filters demodulates and decodes CW characters which are then fed over to the K40 for display on its LCD The K40CW board has an LED bar display that is used to tune CW stations in quickly and accurately Features e 4 Pole Active Bandpass Filter Quadrature Correlation demodulator Fixed tone decode at 690 Hz Cypress CY8C27143 24 PSoC Processor LED tuning display on board PIC12F508 LED controller Transmit Receive Switching Single 5 volt supply requirement Board dimension 2 25 by 3 0 inches Current Draw lt 10 ma Assembly Instructions Bill of Materials Reference K40CW PCB K40CW Printed Circuit Card CY8C27143 PSoC Controller C6482 Dual Op Amp 8 Pin PDIP Description Package Check PIC12F508 Display Controller D1 06 R11 R12 270 Q 5 Resistor R4 R5 R7 10K 5 Resistor 1 4 W Blue R3 R8 33 2K 1 Resistor i1 4wdie RO 1 64K 1 Resistor iame Rer 66 5k 1 Resistor _ _ anse RO 9 76 is Resistor O 1 4WBlue ea er 33 pt capacitor electrolytic C1 05 C6 C10 01 uf 100 VDC capacitor ceramic disc 1 1 uf ceramic capacitor 1 lead space 63 64 68 69 012 pr mylar capacitor Dipped radial Position Ui e Pin DIP so2. GND 5V RGND RO es cz TR o TI B TP2 N ul m J o N SP 88282 4 l a main j 2 U2 cs TD l RE Den R4 Ov K40 CW PCB REV A AGND AF_IN Fig 9 K40FILT PCB Reference Designators K 40CW User s Manual Rev 1 0 2 5 2008 Page 12 K1EL CW Decoder Board Kit K 40CW 1 2 3 4 5 6 7 lt c8 RE S 012uF 66 5K c3 R2 LOW_AF I 012uF 66 5K c Ca c4 R8 p2p 012uF U2A 1 6 R3 a gt AF_IN 7 4 4 TP1 33 2K PAD tF Sibut LMC6482 33 2K R10 LMC6482 1 4 7K R9 AGND per Ri 9 76K GND c5 GND 01uF GND HE sv GND Gio o R5 10K GND 4 AGND 4 33uF oT J c6 1 he io tur a TN sv sv i c2 EN 33uF _ GND ATI Title i K40 CW Reader GND Author m Steve Elliott K1EL Systems GND File Document C bk keyers k40 K40cw SCH k40cw dsn Revision Date Sheets 1 0 June 1 2007 1 of 2 1 2 3 5 6 7 K40CW User s Manual Rev 1 0 2 5 2008 Page 13 K1EL K40CW CW Decoder Board Manual 1 2 3 4 5 6 7 aka lt gt RO G
3. K1EL K40CW CW Decoder Board Manual The K40CW will automatically track the CW speed as it changes and will lock on to a new station s speed within a letter or two Sometimes noise in the background can cause the K40CW to lose speed lock and can fool the speed locking logic Again noise makes it tough to copy The upper Rx speed about 40 to 45 WPM with upper limit influenced by the noise filter setting You can show the current receive WPM by hitting ALT TAB This will momnetarily show the approximate speed of the CW currently being copied by the K40 CWR Note that the speed is determined by the average width of received dits This means that it can be fooled by Farnsworth formatted CW For example if you copy W1AW code practice at 10 WPM the K40CWR will report 18 WPM since the code practice is sent at 10 WPM with a Farnsworth speed of 18 WPM K40CW Settings There are several settings that can be issued from the K40 to configure the K40CW operation 1 Gain can be adjusted to compensate for low or high receiver volume There are eight gain settings Gain is adjusted by holding the Shift key down while turning the speed control As you turn the knob the current setting is displayed momentarily on the LCD display 2 The low pass noise filter is also adjustable There are eight settings from minimal filtering 01 to maximum filtering 08 Filtering is adjusted by holding the ALT key down and turning the speed control As you turn the knob the
4. 40CW User s Manual Rev 1 0 2 5 2008 Page 7 K1EL K40CW CW Decoder Board Manual Every time SHIFT F3 is pressed the modes will advance as follows ASR OFF TXMON OFF ASR OFF TXMON ON ASR ON TXMON OFF ASR ON TXMON ON TAB Toggle Receive Transmit Display Window Unchanged from Original K40 Either incoming or outgoing streams can be displayed The TAB key selects which A blinking cursor is shown in the transmit outgoing window INSERT Receive Transmit Control Modified for K40 rev G When the K40CW module is enabled see ALT F1 command the LCD display will default to the receive window This allows you to view received CW that the K40CW module is decoding If desired you can press insert to pause transmit and type ahead but the display window will remain in receive You can view the transmit window at any time by pressing the TAB key When you are ready to transmit press the insert key again and PTT will be asserted and text in the transmit buffer will be sent As long as you continue to type the K40 will transmit unless you press Insert again When you have typed into the typeahead buffer while paused the SCROLL LED will start blinking to remind you that there is text in the buffer waiting to be sent You can cancel the transmit buffer with the ESC key Insert is a toggle command each press will advance from transmit gt receive or receive gt transmit ESC Abort Clear Buffer unchanged from original K40 ESC can be pre
5. Controller By applying a signal generator to the K40CW audio input and sweeping this from 600 to 800Hz a peak response will be observed at this test point at approximately 690Hz 20 Hz TP2 Audio Ouput of the PSoC s internal 4 pole SCAF filter In the same manner as above a peak response can be seen at 690 Hz This test point can also be configured to show the logic decode of received morse tones such that no tone will produce a 0 volt level while tone present will produce 5 volts The test point is configured with a special diagnostic command K 40CW User s Manual Rev 1 0 2 5 2008 Page 9 K1EL K40CW CW Decoder Board Manual Immediate Commands Key Normal Shift ALT F2 Play Message2 SetLeadin Delay Fe Play Message 6 NA Fe Play Message 8 ToggleTune Fo Play Message 9 NA Table 2 Speed Pot Control Table 3 Buffered Commands D Serial 1 0 DO Serial 4 L Load Loop Count L lt nn gt nn count LO M Insert CR AM M Play Serial DECSZ Loop Table 4 K 40CW User s Manual Rev 1 0 2 5 2008 Page 10 K40CW CW Decoder Board Manual K1EL Fig 6 K40CW PCB Checkplot O O O O O O O O O O 0 0000 25600000 t 0000 O Zb mielela Fig 7 K40FILT PCB Top Solder Layer Page 11 2 5 2008 K 40CW User s Manual Rev 1 0 K1EL K40CW CW Decoder Board Manual Fig 8 K40FILT PCB Bottom Solder Layer
6. Low Signal Level High Signal Level Fig 5 CW Level Indicator LEDs The LED display is a very simple indication of both tuning accuracy and signal strength Note that a change in signal strength will cause movement in the display similar to a signal being tuned in by frequency K 40CW User s Manual Rev 1 0 2 5 2008 Page 6 K1EL K40CW CW Decoder Board Manual Transmitting When the CW reader is enabled the K40 KEY output is used to key your transceiver as it normally would You can either type on the keyboard or use a paddle set to enter letters to transmit When in CWR mode the default display view is receive To view the transmit buffer and see what you are typing hit the TAB key to toggle the view As described previously a handy feature is ASR mode when this is turned on the display will toggle to the transmit view as soon as you start typing When you stop or pause the display will return to receive view Transmit view is identified by an underline cursor that indicates the text entry point The cursor is turned off in the receive view The user can toggle between the receive and transmit views manually by using the TAB key You can scroll back though the buffer ine at a time using the PGUP and PGDN keys Hitting the HOME key returns the buffer back to the active line You can t use END for scrolling that key is used for fast callsign entry While receiving the K40 supports type ahead so you can enter a response message
7. 2 Pin 5 2 5V Pin4 Ground U3 Pin 1 5V Pin8 Ground If you don t see these voltages carefully check your solder connections and look for any shorts or opens The 2 5V bias is the analog referece for the active bandpass filter It is determined by the voltage divider R4 and R5 Install and solder in U2 and U3 Power on again and re measure the voltages to make sure they are still correct Turn power off and on again and watch the LED display you should see a power up LED test in which each LED is turned on and off in sequence Make sure all LEDs light one at a time When the test is over all LEDS will turn off Turn power off again and install U1 power up again and you should see 2 5 volts on 11 12 13 17 pins 1 and 7 TP2 These are analog input and output and should be biased at analog reference Again if you don t see 2 5 volts check the connections on U1 particularly the power pins and bypass caps Remove power after testing Now it s time to check out the K40CW tone filters Connect an audio frequency generator or receiver audio output to the AF input on the K4CW board The level should be around 5V peak to peak preferably a high impedance output 6000 You can use speaker audio out but you may need a higher level If you are using a receiver turn on calibrate or tune in a carrier signal to get a beat note If you are using a signal generator set it to 690 Hz Power up the K40 and ma
8. andwidth of this stage is approx 400 Hz which provides coarse out of band signal rejection A wider bandwidth also allows for component tolerances in the active filter This stage also isolates and protects the PSoC processor from the input The LMC6482 handles large input amplitudes well and clips very cleanly After filtering the audio is fed directly to the PSoC processor The PSoC is a mixed signal device which contains both analog and digital function blocks These blocks as well as the connections between the blocks are programmable This allows a very sophisticated design to be implemented in a very small package The clock that runs the PSoC is contained within the device and is set at 24 MHz The signal chain inside the PSoC is described next First the signal is passed through a programmable gain amplifier to boost low level signal levels This gain can be adjusted via the K40 speed control and SHIFT key Next the signal is fed to a 4 pole bandpass filter that is implemented with an SCAF filter he center frequency is set to 690 Hz with a bandwidth of about 200 Hz The filtered signal is then fed to a tone detector which is implemented with a quadrature correlator The recovered dit and dah intervals are then measured and translated into ASCII letters which are sent to the K40 for display As part of the detection process the amplitude of the filtered CW signal is determined and this information is formatted as a PWM signal which is fed to the dis
9. cket en An accurate DVM or VOM is highly recommended for this project There are several precision 1 resistors that MUST be installed correctly to insure proper operation The color codes on these resistors can be confusing and an ohmmeter is a very reliable way to determine which resistor is which Other than that the assembly of the K40CW is very easy all you need is a low wattage soldering iron some solder a few pieces of hook up wire a good pair of wire cutters and small pliers You will need an assembled working K40 board to test and check out the K40CW board These instructions will take you through a step by step process that will test portions as you go This will make debugging much easier since if a problem arises you will be able to locate the source right away First inventory and identify all parts before you start using the Bill of Materials This will allow the assembly to proceed smoothly Use your ohmmeter to sort the resistors by value Email us about any shortages and we ll send them to you After inventory carefully inspect the PCB for any solder shorts or other obvious defects it s easier to find them before placing parts Start with the six LEDs the easiest way to do this is to install one of the center ones first Align the LED carefully to be in the center of the silkscreen with front edge flush with the front edge of the PCB Carefully solder in place One by one install the remaining five LEDs in
10. current setting is displayed momentarily on the LCD display 3 Inter element spacing allowance can be adjusted too This helps compensate for incorrect spacing between dits and dahs which can cause letters to be run together or broken apart This has four ranges and is adjusted by holding the CTL key down while turning the speed pot Smaller values expect less space between elements fixes case where an R prints as ETE while large values expect more space fixes case where ETE prints as R ASR Mode automatically toggles the display window from receive to transmit when the user types on the keyboard When ASR is enabled you must pause the output INSERT key before typing into the transmit buffer When insert is pressed again the transmit buffer is released and sent TXMON mode allows both paddled and keyboarded Morse to be shown in the Receive window as a convenience Received letters are displayed in upper case while transmitted letters are displayed in lower case Normally only received characters are displayed in the receive window No matter what mode you are in you can always toggle between the transmit and receive windows with the TAB key The accuracy of CW decoding can vary as a signal fades in and out With very deep fades the K40 may print an erroneous character or get out of sync for a couple of characters You can turn the K40CW module off using the ALT F1 command With the module turned off it will draw minimal power O O O O O s
11. i 01UF D6 LED3 S Reno GND Ut 1 8 7 1 D5 LED3 LOW_AF PO 5 gt Po 4 TP2 cho S tr PAD 2 Pofa cyecer143 PORI N n Pa 3 pit P Pro 2 D4 LED3 U R11 te PAD N 270 D3 LED3 GND N x GND SV T D2 LEDS I NY o D1 LED3 R12 R7 Na 270 10K p 1 8 2 12F508 7 c10 3 6 01uF 4 MH_125 x so G A xO m L GND 1 MH_125 M O M GND MH 125 dl i MH_125 Title x O He K40 CW Reader Author m uli Steve Elliott K1EL Systems OND File Document C bk keyers k40 K40cm SCH k40cw dsn Revision Date Sheets 1 0 June 1 2007 2of2 1 2 3 4 5 6 7 K 40CW User s Manual Rev 1 0 2 5 2008 Page 14 K1EL CW Decoder Board Kit K 40CW K40 CW Rig Connections K40 Enclosure Transceiver KEY OUT Keyed Low G 5V PtP max Receiver Audio Line out Ground Figure 11 Typical K40CW to Rig Interconnect Product Information The K 40CW is fully guaranteed and if you are not satisfied please return the kit for a full refund Any questions will be handled by snail mail or e mail via these addresses Steven T Elliott KIEL or e mail KTIELQk1el com 43 Meadowcrest Drive Bedford NH 03110 USA Watch the K1EL Website for latest updates and new products http www k1el com While best efforts have been made to insure the K40CW design is as complete and reliable as possible it is still possible to cause equipment damage or incur personal injury if the K40CW k
12. it is not used as intended is connected incorrectly or modified in any way K1EL can not be held responsible in these events K40CW User s Manual Rev 1 0 2 5 2008 Page 15
13. ke sure that it is in CWR ON mode Press ALT F1 Tune up and down slowly until you see some activity on the LED display You may have to play with the audio level As you tune you will first see LEDs light on the left side and then peak to the right as you tune through 690 Hz The maximum swing should be at 690 Hz If your audio level is too low you may not see a full swing tune Try increasing the gain by holding down the shift key and turning the speed control If you are having problems read through the theory of operations and check the signal path through the filter TP1 and TP2 are useful for this see page 7 Now let s try to tune in some CW stations Connect AFIN to your receiver s audio output Make sure you are still in CW receive mode ALT F1 When no station is tuned in the LEDs should be out or flicker dimly You may see an occasional random character if there is lot of noise on the band As you approach proper tuning you will see a deflection across the display in sync with the keyed CW As soon as you are tuned in letters will appear on the K40 display The K40CW does a pretty good job of following bad sending but it can t copy letters that are run together or badly timed dits and dahs You can improve noise immunity to some degree with the adjustable noise filter This is adjusted by holding down the ALT key and turning the speed control There are eight levels with 0 meaning less filtering up to 8 for increased filteri
14. ng Higher filtering will compromise faster WPM copy That s it After reading through the theory of operations it s on to the command section to learn about the K40CW command set K 40CW User s Manual Rev 1 0 Page 2 K1EL CW Decoder Board Kit K 40CW Fig 1 Assembled K40 CW PC Board K40CW User s Manual Rev 1 0 2 5 2008 Page 3 K1EL K40CW CW Decoder Board Manual Wiring the K40 CW Module into the K40 Enclosure The K40 enclosure has a slot to place the K40 CW module Before attaching the board to the enclosure there are some wires that must be attached There are five wires between the K40 PCB and the K40 CWR PCB as shown below In addition there are two wires from the K40CW board to the AF IN RCA jack on the K40 enclosure This is the jack the receiver audio is connected to TR RO G TI 5V Audio Input CW KEY is pulled low from Receiver pla on Key down This is wired to the AF IN RCA jack on the K40 Enclosure KEY and PTT are both open collector transistor outputs 50 VDC 100ma max to ground Audio Input impedance is approx 1K ohms 5 volts PtP maximum PTT is pulled low on transmit Fig 3 K40 to K40 FILT Interconnect K 40CW User s Manual Rev 1 0 2 5 2008 Page 4 K1EL K40CW CW Decoder Board Manual Theory of Operation The following block diagram Figure 4 shows the basic sections of the K40CW board Audio from the receiver is filtered through an initial active filter stage The b
15. om 1 to 8 CTL SPEED Control new for K40 rev G If you press and hold the CTL key while turning the Speed Control you can adjust the amount of inter element space the decoder will use when making a decision to end a letter This can help in situations where ops use too much or too little space between dits and dahs For example if too much space is used dit dah dit could be decoded to E T E instead of R It can also help where faster senders do not allow enough space between letters For example dit dah dah dit is decoded to P instead of A N There are four spacing ranges 00 to 03 where smaller values reduce inter element spacing and larger values increase spacing ALT TAB Show Receive WPM new for K40 rev G Momentarily shows the Rx WPM in the LCD display K 40CW User s Manual Rev 1 0 2 5 2008 Page 8 K1EL K40CW CW Decoder Board Manual K40CW Specifications CW Receive Fixed Rx Tone 690 Hz Input Level 1V nominal 5V max peak to peak Speed Rate 10 to 45 WPM Tuning Indication Six LEDs frequency bar graph auto squelch Gain Settings Eight gain levels Noise Filtering Eight Digital low pass filter settings Inter element Spacing Four spacing intervals narrow to wide Speed Read Back Displayed upon key press ASR Mode Automatic display buffer toggle K40 CW PCB Tesipoints There are two test points that can be used to verify the operation of the K40 CW PCB TP1 Audio output of the 4 pole active filter before entering the PSoC
16. ot using the END key and reuse the above message over and over again Note that the CALL token C is used to call the message in F12 and then return If you did insert a AC before the message it would jump to the F12 slot and stop when that message finished Command Description by Key There are no changes to the existing K40 commands please refer to the K40 manual for information on these There are only a couple of new commands added to support the K40CW module and are only available in chipset revision G or higher ALT F1 Toggle K40CW module on and off When this key is pressed it will turn the K40CW module on or off A message is shown on the display that states which one When the K40CW module is off it will not respond to audio input and will not send any decoded CW to the K40 SHIFT F3 Set ASR and TX Monitor Modes This is anew command added for K40CW support With ASR on the K40 will toggle back and forth between receive and transmit display buffers when characters are typed on the keyboard This frees you from having to hit the TAB key to flip the windows back and forth Actual transmit is still controlled by the INSERT key If you want to type ahead and not transmit pause the output with the INSERT key When you are ready to release the buffer hit INSERT again A blinking CAPS LOCK LED on the keyboard will indicate when output is paused You can hold the transmit display for a longer period of time by increasing the Tail time K
17. play PIC U3 which lights a six LED bar graph display LMC6482 690Hz PIC12C508 o i Input o Audio 3 AF Bandpass o LEDs o gt da Tone runn 690Hz Decoder Decoded Dits Dahs TI To From Serial ASCII K40 i RO Comm Translation PSoC PSoC Fig 4 K40CW Board Block Diagram Using the K40CW module It s easy to use the K40CW There are just a few things to keep in mind The filters in the K40CW design are fixed at 690 Hz This just means that you need to adjust your receiver so that its passband is centered on 690 Hz When you hear a station slowly tune the station while watching the LED display on the K40CW module Watch for a peak LED movement to the right of the display You will see a peak as you pass though 690 Hz Once you have the station tuned in properly CW will be decoded and displayed Although the filtering on the K40CW is good there are two conditions that it has difficulty with Very strong static crashes and very strong adjacent stations So if either of these things is present you will see a decrease in the quality of copied CW As mentioned before a bad fist is a bad fist and there s not much that can be done to decode one Characters run together poorly constructed letters and widely varying code speed is not easy to copy You will also find that the K40CW will respond to noise or off tuned signals and display garbage characters on the LCD display K 40CW User s Manual Rev 1 0 2 5 2008 Page 5
18. ssed at any time to abort a message abort a command or to clear the type ahead buffer If you press ESC while entering a message the message buffer will be cleared and you effectively can start over at the beginning Note You need to press ENTER to exit message entry mode ESC just clears what you have entered and starts you over ALT Speed Conirol new for K40 rev G If you press and hold the ALT key while you turn the Speed Control the K40CW noise filter is adjusted There are eight settings ranging from minimal filtering 1 to maximum filtering 8 This controls the cutoff of the digital low pass filter in the CW demodulator With higher settings of filtering the K40CW will not respond to shorter bursts of noise and ignore them Higher filter settings reduces the K40CW s ability to copy very fast CW SHIFT SPEED Control new for K40 rev G If you press and hold the SHIFT key while you turn the Speed Control the K40CW gain is adjusted This allows you to tailor the K40CW module for differing input levels Depending on what the source of the audio input is line out headphone jack 600 ohm output speaker output the signal level can vary widely Adjustable gain allows you to compensate for this For best result adjust the gain so that the loudest signal just barely lights the right most LED This insures that you have sufficient gain to copy weak signals while not overdriving the K40CW module on strong signals There are eight gain levels fr
19. suring that each LED is spaced evenly and is flush with the front edge solder one lead on each first so can go back and individually tweak them before soldering the second lead It s important to K40CW User s Manual Rev 1 0 Page 1 K1EL K40CW CW Decoder Board Manual 10 do a good job so that the LEDs fit correctly through the front panel of the enclosure Next install the watt resistors Verify each value with the Bill of Materials on Page 9 and Fig 7 on page 11 Double check to make sure you place them correctly start with R1 and go all the way through to R12 OOUOL O O LU LI Install the DIP socket at U1 Align the notch in the socket with the silkscreen It s easy to accidentally bridge adjacent pins when soldering so take your time Install and solder the capacitors Two caps C2 and C7 have polarity markers that must be observed On both caps the long lead is the positive lead and should be installed closest to the silkscreen legend The square pad is the positive side Now wire the K40CW board to the K40 board as shown in Fig on Page If you purchased the K40 enclosure follow the detailed wiring harness instructions Note that there are three signal connections 5V and two grounds After this step but before installing any ICs turn the K40 power on and verify the following voltages Ul Pin 8 5V Pin4 Ground U2 Pin 8 5V Pin4 Ground U2 Pin 3 2 5V Pin4 Ground U
20. while reading an incoming message You can quickly toggle to the Tx buffer with the TAB key to check a spelling or see where you are Hit TAB again to get back to the incoming display The Caps Lock light on the keyboard will flash when there are characters in queue waiting to be sent The transmit monitor command Shift F4 is useful in some cases It allows you to monitor real time transmit progress in the receive window and will show messages fully expanded instead of message token letters When TX monitor is on the transmit stream is printed in lower case in the Rx window The LCD window is not toggled back and forth with transmit receive in this mode since everything can be seen in one window You still can toggle the display manually with the TAB key TX monitor can produce quite a cluttered display and I only use it to verify that messages are being sent the way expect It s useful in contests when you are using the fast callsign entry feature and want to be sure you entered callsigns correctly A nice K40 feature is fast callsign entry Pressing the END key will open up a small window in the upper left corner of the display where you can enter a callsign When you hit return the callsign will be copied into the F12 message slot This is great for contest exchanges Try entering a message formatted like this AKAM AC lt F12 gt DE K1EL 5NN 5NN NH NH QSL C lt F12 gt DE K1EL QSL MK Now you can quickly enter different callsigns into the F12 sl
Download Pdf Manuals
Related Search