ULTRASOUND DETECTOR D980 OPERATING INSTRUCTIONS
Contents
1. it is possible to locate the freguency resulting in a zero Hz output freguency the tuned freguency then eguals the freguency of the ultrasound NOTE The example above is only intended to illustrate the heterodyne principle Constant freguency sounds are very rare in practice so in most cases you will only be able to get an approximate measure of the signal freguency In the scanning mode AUTO MAN switch in the SCANNER CONTROLS section set to AUTO the detector rapidly scans a selected freguency range up and down searching for sounds If a sound is detected the scanning is inhibited for a few seconds allowing the user to read the display The scanning range is determined by the settings of the freguency control the large knob also used to tune the heterodyne system and the SCAN RANGE control The freguency control determines the lower freguency limit while the SCAN RANGE control determines the width of the scanning range To set the scanning range adjust the two controls mentioned above while at the same time noting the freguencies shown on the display The scanning is made guite rapidly so it is necessary to observe the display carefully to determine the obtained scanning range Next the amplitude threshold should be adjusted As was mentioned above when a sound is detected the scanning is inhibited The LEVEL control is used to set the level above which the sound is considered to be detected Turning the control clockwise decr2. transforms the harmonic frequency component not the fundamental This situation is relatively uncommon Nevertheless it is important to remember that it occasionally may occur c The time expansion system This technigue is similar to recording a sound on a tape recorder and then replaying the tape at a reduced speed However in the D980 the signal is not stored on a magnetic tape but in a digital memory The time expansion principle is unigue in the sense that it is the only ultrasound conversion system that retains virtually all characteristics of the original signal so time expanded signals are well suited for many forms of advanced signal analysis e g with our sound analysis software package BatSound The time expansion factor is 10 on the standard version of the D980 a special version with selectable time expansion factor 10 or 20 is also available The maximum recording time is 3 seconds 12 seconds as option Please note that the text 3 SEC 12 SEC on the front panel label is present on both the 3 seconds and 12 seconds model It should be disregarded on the 3 seconds model The time expansion system can be used either in manual or automatic mode In the manual mode the user initiates the sound capture by pushing a switch while the detector does this automatically in the automatic mode The automatic mode is adapted for the 3 seconds version of the D980 i e the detector will be automatically armed again after replaying
3. 00 kHz the time expansion system 10 150 kHz into the audible freguency range Although the main application for the D980 is studying bioacoustic ultrasound bats rodents bush crickets etc the detector can be used in many other situations where detection of ultrasound is involved ultrasonic intruder systems leaks in pressurized systems corona discharges etc GETTING STARTED The detector is powered from two 9 V batteries A set of alkaline batteries will last for appr 12 hours Remove the battery compartment lid make sure the ON OFF switch is in the OFF position and insert two new batteries Please note the polarity and make sure the detector s battery connector snaps firmly into position over the corresponding connector of the battery Then turn on the detector by setting the ON OFF switch located next to the microphone in the ON position The LCD display now shows the tuned frequency heterodyne system only To test the basic operation modes of the detector please perform the following steps Connect a set of stereo headphones to the PHONES jack Set both PHONES switches LEFT and RIGHT to the H heterodyne position Set the HF GAIN control to maximum sensitivity turn it fully counter clockwise and adjust the VOLUME control so that a weak noise is heard in the headphones Set the SCANNER CONTROLS AUTO MAN switch in the MAN position Remove the red plastic protection cap from the microphone by gently pulling it o
4. 30 seconds of time expanded sound To use the automatic mode set the AUTO MAN switch located to the left of the OVERLOAD indicator to the AUTO position and set the TRIG LEVEL control to a suitable level Perform a few test recordings to determine a suitable setting In the automatic mode the recently made recording is replayed once and then the detector waits for the next signal to record If the TRIG LEVEL is set maximum counter clockwise the detector will be triggered from very weak signals and this means that in practice the detector will make a new recording immediately after replaying the previous recording To use the manual mode set the AUTO MAN switch located to the left of the OVERLOAD indicator to the MAN position The recording is initiated by pushing the TE START switch This places the detector in the armed mode The setting of the TRIG LEVEL determines when the recording is interrupted Three sub modes are available i TRIG LEVEL is set maximum counter clockwise In this case the recording is interrupted immediately or rather as soon as a preset time has elapsed This delay is to make sure that the time expansion memory will be filled Using this mode a recording of 3 12 seconds will be made starting from when the TE START button was pushed ii TRIG LEVEL is set to an intermediate position In this case the recording is interrupted shortly after the signal exceeds the level determined by the TRIG LEVEL In or
5. 50 kHz time expansion 0 2 kHz 3 5 mm stereo jack load impedance 4 ohms or greater 3 x phono jacks for tape recorder appr 500 mV rms max 4 kohm Phono jack appr 500 mV rms max 1 kohm 350 kHz 1M x 8 bits 12 seconds version 4M x 8 bits 8 bits 3 seconds selectable 3 12 seconds on 12 seconds version 10 selectable 10 or 20 on reguest 1 second 2 x IEC 6LF22 9V 39 mA typ including microphone 170 x 100 x 65 mm incl knobs etc 600 g including battery Yes Overload indicator adjustable input gain Using the detector in intense electromagnetic fields may cause interference and or temporary signal loss
6. FREQ DIV HET or TIME EXP jacks phono jacks to make recordings of the transformed sounds or to the HF jack to record the unaltered signal from the microphone signal Typically the HF output is used to record the original high frequency signal on a device capable of recording such high frequencies an instrumentation tape recorder or a computer with a high speed sound card In order to facilitate recording of spoken comments there is also a COMMENT push button Pressing this switch makes the microphone signal temporarily available at the HET output If the input impedance of the tape recorder is very low lower than ca 5 kohms the signal levels in the detector will be decreased resulting in a weaker output to the headphones Any tape recorder connected to the TAPE output should be battery powered The maximum length of any connected cable is 1 meter TROUBLE SHOOTING The D980 is a very carefully designed instrument If however a malfunction would occur it is hoped that this check list will help to correct the fault Symptom No sound no light from LED s No sound weak sound Sudden crackles and or noise Acoustic feedback No sound one or both LED s flashes The heterodyne freguency control does not work after turning on the power Poor tonal guality from the freguency division system Possible cause and renedy Dead batteries Replace batteries HF GAIN or VOLUME control is set too lo
7. ULTRASOUND DETECTOR D980 OPERATING INSTRUCTIONS SCAI GE LOCKED AUTO MAN LEVEL L SCANNER CONTROLS TE H FD TE H FO O amp TE STOP 3 SEC 12 SEC 6 amp e BATTERY LOW TE START AUTO MAN OVERLOAD VOLUME D 980 ULTRASOUND DETECTOR Pettersson Elektronik AB Pettersson A Elektronik AB Tallbacksv gen 51 SE 756 45 UPPSALA Sweden Phone 46 1830 3880 Fax 46 1830 3840 e mail info batsound com Intemet www batsound com Guarantee This product is guaranteed against defects in material and workmanship for a period of one year from the date of purchase In order for the guarantee to be granted a proof of purchase normally the original invoice receipt is reguired and the serial number label must not be removed from the product Pettersson Elektronik will repair or replace the product if it proves to be defective during the guarantee period provided it is returned to us No other guarantee is expressed or implied Pettersson Elektronik assumes no responsibility for conseguential damages of any kind The guarantee covers none of the following 1 Damage to the product resulting from abuse and misuse including but not limited to a the failure to use this product for its normal purpose or in accordance with Pettersson Elektronik s instructions on the proper use and maintenance of this product and b the installation or the use of this product in a manner inconsistent with the technical or safety standards in force in t
8. adphones and PHONES switches Any set of stereo headphones with a standard 3 5 mm stereo plug and an impedance of 4 ohms or more can be used The headphones should be connected to the PHONES jack on the right hand side of the detector The output level to the headphones is adjusted with the VOLUME control The setting of the PHONES switches determine which system is fed to the headphones It is possible to listen to two of the three systems simultaneously The setting of the PHONES switches and the VOLUME control do not affect the tape recorder outputs FREO DIV HET and TIME EXP The HF GAIN and OVERLOAD indicator The HF GAIN control is located on the left hand side of the microphone Maximum sensitivity is obtained when the knob is turned maximum counter clockwise If the ultrasound to be monitored is too loud the input stage of the detector will be overloaded This is indicated by the flashing of the OVERLOAD indicator Overloading does not cause any damage to the detector but the signals processed by the detector will become distorted Hence it is suggested that the HF gain control be adjusted if the OVERLOAD indicator flashes freguently particularly if the transformed signals will be used for sound analysis The outputs The output jacks are all located m the right hand side of the detector The transformed sounds are monitored through headphones connected to the PHONES jack 3 5 mm stereo plug A tape recorder can be connected to the
9. cil or similar pointed object should be used The switch was deliberately positioned this way to avoid accidentally changing the setting To test the freguency division system please repeat the test you performed on the heterodyne system above Finally let s check out the time expansion system The time expansion system is similar to recording a sound on a tape recorder and then replaying the recorded signal at slower speed In the detector the signal is stored in a digital memory The D980 allows recording of signals up to 3 seconds or 12 seconds of length depending on the size of the memory The 12 seconds version has a switch by means of which the recording time can be selected either 3 or 12 seconds If you have this version set the switch to 3 seconds Push the TE START switch once and set both of the PHONES switches to the TE time expansion position and the TRIG LEVEL maximum clockwise Push the TE START switch again to start recording into the digital memory Nothing is heard in the headphones at this time Snap your fingers near the microphone for a few seconds and then push the TE STOP switch to interrupt the recording Immediately after pushing the TE STOP switch the detector starts to replay the recorded signal at a tenth of the original speed Hence replaying the 3 seconds seguence once will take 30 seconds The detector will remain in this mode and replay the recorded seguence in an end less loop fashion until the TE START button
10. ctor can be used even if the BATTERY LOW indicator is on The sensitivity is lower and the risk for signal distortion increases though The microphone The microphone is a solid dielectric capacitance microphone with a built in preamplifier This type of microphone reguires a polarizing voltage about 200 volts which is generated by a DC DC converter in the detector This voltage is present at the microphone socket To remove the microphone from the detector unscrew the grooved green ring and gently pull the microphone off the socket When attaching the microphone again make sure the ring is properly tightened If the microphone membrane has been worn or punctured it may be necessary to replace it The microphone capsule the upper part of the microphone with the membrane is replaceable and is available as a spare part To remove the microphone capsule unscrew the lock screw see figure below slightly with a suitable screwdriver and pull the microphone capsule from the microphone housing Do not unscrew any other screws on the microphone this may cause damage to the microphone and or the microphone capsule NOTE The microphone membrane is easy to damage At all times touching the microphone membrane should be avoided If the microphone membrane has been punctured electrical discharges may occur Although the energy stored in the microphone capsule is very limited the detector should not be used in areas with explosive gas The he
11. der not to miss the beginning of the signal a pre trigger time of ca 1 second is included here see the figure below Trigger moment I Trigger level IN Time ms 0 1000 3000 Start End of R of recording recording iii TRIG LEVEL is set maximum clockwise In this case the recording is started by pushing the TE START button and stopped by pushing the TE STOP button i e the user has full control over the recording process This mode is often the most useful for making recordings manually Using this mode a recording of the last 3 12 seconds prior to pushing the TE STOP button will be made NOTE Immediately afte r turning the power on the time expansion memory contains a random high level signal In order to protect your hearing always decrease the headphones volume prior to turning the power on and then press the TE START button to remove the initial signal f rom the memory GENERAL TECHNICAL DESCRIPTION The batteries The detector is powered from two 9V batteries Alkaline types are recommended and will last for approximately 12 hours Freguent use of the display light the light switch is located to the left of the freguency control results in shorter battery life time When the battery voltage has decreased to about 7 volts the BATTERY LOW indicator will light up One failing battery results in a moderate light while two failing batteries makes the indicator light more intensively The dete
12. e mode The manual mode is described first If the freguency control is adjusted to give a display reading of 30 kHz the range from appr 25 to 35 kHz will be transformed This is illustrated in the figure below Ultrasound before conversion te f kHz 0 10 20 40 50 Audible sound after conversion lt oe f kHz 0 10 20 30 40 50 Let s assume an ultrasonic signal with constant frequency is emitted The frequency of the transformed signal i e the signal heard in the headphones equals the difference between the frequency of the ultrasound and the tuned displayed frequency In this case when the detector is tuned to 30 kHz this means that an ultrasound of either 31 or 29 kHz will be transformed into 1 kHz When the frequency control of the D980 is turned from low frequencies to higher a high pitched tone will be heard in the loudspeaker when the frequency setting is appr 5 kHz lower than the frequency of the ultrasound source The closer the tuned freguency comes to the ultrasound s freguency the lower the freguency of the loudspeaker tone gets When both freguencies are identical the resulting output freguency becomes zero i e nothing is heard in the headphones If you continue to turn the freguency control towards higher freguencies a tone will again be heard in the loudspeaker however this time the freguency will increase as the tuned freguency increases By tuning the freguency control up and down
13. eases the threshold level When a sound is detected the scanning stops for a few seconds and the LOCKED indicator lights up The display can be read to obtain an approximate value of the frequency of the signal During the scanning inhibit period a slight frequency drift may occur b The freguency division system Freguency division means that the freguency of the ultrasound is changed with a constant factor of 10 or 20 depending on the setting of the freguency division switch located on the right hand side of the detector below the PHONES jack If the freguency division switch is set to 10 a freguency of 40 kHz becomes 4 kHz a freguency of 50 kHz becomes 5 kHz etc Using this system any activity over the entire freguency range 10 200 kHz can be constantly monitored Furthermore the shape of the transformed signal closely follows that of the original signal as shown in the figure below 8 The frequency division is obtained by counting the number of zero crossings made by the original signal An output signal with one zero crossing for each ten twenty zero crossings of the original signal is then generated Normally this gives an output signal with a frequency of one tenth of the original frequency However if the original signal has a strong harmonic component extra zero crossings will occur and the resulting output frequency will be higher than that corresponding to the fundamental frequency the system
14. ff the microphone You should avoid touching the microphone membrane Then turn the large frequency knob to give a display reading of approximately 20 kHz and gently snap your fingers near the microphone A scraping sound should then be heard in the headphones Another good ultrasound source is a jingling bunch of keys The frequency control works in the following way The display shows the center of the frequency range approximately 10 kHz wide to be transformed If the control is set to 30 kHz you can listen to ultrasonic frequencies between approximately 25 and 35 kHz Repeat the finger snapping exercise while tuning the frequency control from 10 kHz and upwards Note how the level of the sound changes as the tuned frequency increases This depends on the spectral composition of the ultrasound most of the energy in the signal is contained in the lower frequency range The heterodyne system can also be used in an automatically scanning mode For more information about this mode please refer to the section about the heterodyne system Next let s have a look at the frequency division system The frequency division system is very easy to use since the detector will cover the full ultrasonic range without having to adjust the freguency control Set the two PHONES switches to the FD freguency division position and the 10 20 switch located below the PHONES jack to the 10 position In order to change the setting of the 10 20 switch a pen
15. he country where the product is used 2 Damage to the product resulting from non authorized modifications made to the product 3 Repairs done by non authorized technicians 4 Accidents or similar causes beyond the control of Pettersson Elektronik including but not limited to lightning water fire and public disturbances D940 Ultrasound detector The D940 ultrasound detector is identical to the D980 detector except that it does not have a time expansion system Hence this manual also covers the D940 if all references to the time expansion system are disregarded O Pettersson Elektronik AB 2001 INTRODUCTION The ultrasound detector D980 is an easy to handle and very powerful instrument for conversion of ultrasound to audible sound It is primarily intended for studying bats and other animals emitting ultrasound The detector has three independent ultrasound conversion systems a heterodyne system a freguency division and a time expansion system The detector is eguipped with a digital display to provide very accurate readings of the tuned freguency in heterodyne mode Before using the detector please read the following information carefully Further information on the identification of different bat species using ultrasound detectors may be found in the literature e g Barataud The inaudible world or Russ The bats of Britain and Ireland available from Pettersson Elektronik The D980 transforms ultrasound in the range 10 2
16. is pushed again There are also other ways to make the detector start and stop recording into the time expansion memory by itself Please refer to the section about the time expansion system for more information about this After using the detector please put the microphone protection cap back to avoid damaging the sensitive microphone membrane Many electronic devices such as TV sets computers and electronic watches also emit ultrasound Such ultrasound sources can be handy to test the detector but may also cause undesired interference If you encounter any problems during the test of the detector please refer to the Trouble shooting section THE ULTRASOUND CONVERSION SYSTEMS a The heterodyne system There are several different principles to convert ultrasound into audible sound As mentioned above one of the systems in the D980 is based on the heterodyne principle This technigue means that a limited freguency range is selected for conversion into the audible range Obviously this also means that only a small fraction of the wide band noise will be made audible at each time so the audible noise level is low in a heterodyne detector Hence it is possible to detect very weak signals with this system The heterodyne system in the D980 can be used either in the normal mode which reguires manually tuning the freguency control or in an automatically scanning mode The AUTO MAN switch in the SCANNER CONTROLS section is used to change th
17. w Adjust the controls Defective headphones Replace headphones Low battery voltage Replace batteries Damaged microphone capsule Replace capsule Capsule not properly attached Check contact spring under microphone capsule Damaged microphone capsule See above Capsule not properly attached See above Microphone detector has been exposed to high humidity Allow the system to dry Microphone too close to the headphones Direct the microphone away from the headphones Reduce the headphones volume One battery has low voltage or is incorrectly inserted Check battery voltage and battery connectors Adjust clean connectors if necessary The scanner AUTO MAN switch is in the AUTO position Change it to the MAN position and then back to AUTO again The 10 20 switch is not properly set Make sure that the switch is pushed all the way to its end position NOTE There are no user serviceable parts inside the detector Always refer servicing to qualified service personnel Technical specifications Type Freguency range Display accuracy Headphones output Audio outputs High freguency output Time expansion system Sampling freguency Memory size Resolution Storage time Time expansion factor Pre trigger Batteries Ouiescent current Size Weight Comment switch Miscellaneous Heterodyne freguency division 10 or 20 and time expansion x10 10 200 kHz freguency division and heterodyne 10 1
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