INSTRUCTIONS MODEL AVB2-TC-C 400 VOLT MONOCYCLE GENERATOR WITH 100 - 200 MHz VARIABLE CENTER FREQUENCY SERIAL NUMBER: ____________ __________________________________________________________________ 2 WARRANTY Avtech Electrosystems Ltd. warrants products of its manufacture to be f ree from defects in material and workmanship under conditions of normal use. If, within one year after delivery to the original owner, and after prepaid return by the origina l owner, this Avtech product is found to be defective, Avtech shall at its option repair or replace said defective item. This warranty does not apply to units which have been dissembled, modified or subjected to conditions exceeding the applicable specificat ions or ratings. This warranty is the extent of the obligation assumed by Avtech with re spect to this product and no other warranty or guarantee is either expressed or impli ed. TECHNICAL SUPPORT Phone: 613-226-5772 or 1-800-265-6681 Fax: 613-226-2802 or 1-800-561-1970 E-mail: info@avtechpulse.com World Wide Web: http://www.avtechpulse.com __________________________________________________________________ 3 TABLE OF CONTENTS WARRANTY_______________________________________________________________ ___2 TECHNICAL SUPPORT______________________________________________________ __2 TABLE OF CONTENTS______________________________________________________ ___3 INTRODUCTION___________________________________________________________ ___4 AVAILABLE OPTIONS______________________________________________________ _______4 SPECIFICATIONS_________________________________________________________ ____5 INSTALLATION___________________________________________________________ ____6 VISUAL CHECK___________________________________________________________ ________6 PLUGGING IN THE INSTRUMENT_____________________________________________ _____6 FRONT PANEL CONTROLS___________________________________________________ __8 REAR PANEL CONTROLS____________________________________________________ _10 GENERAL INFORMATION____________________________________________________ 11 BASIC TEST ARRANGEMENT_________________________________________________ ____11 MINIMIZING WAVEFORM DISTORTIONS______________________________________12 USE 50 TRANSMISSION LINES AND LOADS_______________________________________12 USE LOW-INDUCTANCE LOADS_______________________________________________ ____12 PREVENTING DAMAGE______________________________________________________ 12 OPTIONS________________________________________________________________ ____13 -OS OPTION_____________________________________________________________ _________13 -EA OPTION_____________________________________________________________ _________13 -EF OPTION_____________________________________________________________ _________13 MECHANICAL INFORMATION________________________________________________1 4 TOP COVER REMOVAL______________________________________________________ _____14 ELECTROMAGNETIC INTERFERENCE___________________________________________ _14 POWER SUPPLY AND FUSE REPLACEMENT____________________________________15 PERFORMANCE CHECK SHEET_______________________________________________1 7 Manual Reference: /fileserver1/officefiles/instructword/avb/x.doc, crea ted July 12, 2002 __________________________________________________________________ 4 INTRODUCTION The AVB2-TC-C monocycle generator can generate monocycle waveforms with amplitudes of up to 400V (peak to peak) and pulse repetition rates of u p to 20 kHz. The center frequency of the monocycle is variable using a front-panel o ne-turn dial, from 100 to 200 MHz. The AVB2-TC-C may be triggered by the internal oscillator, or by an ext ernal TTL-level pulse. AVAILABLE OPTIONS The AVB2-TC-C is available with several options: “-EA” Option: allows the output amplitude to be controlled by an extern ally generated 0 to +10V analog control voltage. “-EF” Option: allows the center frequency to be controlled by an extern ally generated 0 to +10V analog control voltage. "-OS" Option: allows an externally generated DC offset to be added to t he output. __________________________________________________________________ 5 SPECIFICATIONS Model1: AVB2-TC-C Center Frequency Range: 100-200 MHz Center Frequency Tuning: Tunes full range, using a front-panel one-turn control2. Amplitude2: (Vpp, 50 Ohms) 0 to 400 Maximum pulse repetition rate: 20 kHz Spurious signals: (WRT peak) 26 dB Propagation delay:  100 ns (Ext trig in to pulse out) Jitter:  100 ps (Ext trig in to pulse out) DC offset option3: Apply required DC offset ( 50 Volts, 250 mA max) to back-panel solder terminals Trigger required: Ext trig mode: +5 Volts, 50 to 500 ns (TTL) Sync delay: Sync out to pulse out: Variable 0 to 200 ns Sync output: + 3 Volts, 200 ns, will drive 50 Ohm loads Connectors: Out, Trig/Sync: BNC Power requirements: 120/240 Volts (switchable) 50 - 60 Hz Dimensions (H x W x D): 100 mm x 430 mm x 375 mm (3.9” x 17” x 14.8”) 1) -C suffix indicates stand-alone lab instrument with internal clock and line powering. 2) For electronic control (0 to +10V) of amplitude or frequency suffix the model number with -EA or EF. Electronic control units also include the standard front-panel one-turn controls. 3) For DC offset option suffix model number with -OS. __________________________________________________________________ 6 INSTALLATION VISUAL CHECK After unpacking the instrument, examine to ensure that it has not been damaged in shipment. Visually inspect all connectors, knobs, and handles. Confirm that a power cord is with the instrument. If the instrument has be en damaged, file a claim immediately with the company that transported the instrument. PLUGGING IN THE INSTRUMENT Examine the rear of the instrument. There will be a male power receptacle, a fuse holder and the edge of the power selector card visible. Confirm that th e power selector card is in the correct orientation. For AC line voltages of 110-120V, the power selector card should be ins talled so that the “120” marking is visible from the rear of the instrument, as shown below: For AC line voltages of 220-240V, the power selector card should be ins talled so that the “240” marking is visible from the rear of the instrument, as shown below: __________________________________________________________________ 7 If it is not set for the proper voltage, remove the fuse and then grasp the card with a pair of pliers and remove it. Rotate horizontally through 180 degrees. Reins tall the card and the correct fuse. In the 120V setting, a 0.5A slow blow fuse is required. In the 240V set ting, a 0.25A slow blow fuse is required. __________________________________________________________________ 8 FRONT PANEL CONTROLS 1. P OWER Switch . The POWER push button switch applies AC prime power to the primaries of the transformer, turning the instrument on. The push butto n lamp (#382 type) is connected to the internal +15V DC supply. 2. R EPETITION RATE Controls . Varies PRF as follows: RANGE 1 2 Hz - 20 Hz RANGE 2 20 Hz - 200 Hz RANGE 3 200 Hz - 2 kHz RANGE 4 2 kHz - 20 kHz 3. D ELAY Control . Controls the relative delay between the reference out put pulse provided at the TRIG output (4) and the main output (7). This delay is variable over the range of 0 to about 1.0 us. The TRIG output precedes the main outp ut when the ADVANCE-DELAY switch is in the ADVANCE position and lags when the switc h is in the DELAY position. 4. T RIG Connector . When the MODE switch (item 8) is set to the “EXT” pos ition, a TTL-level pulse applied to this connector will trigger the instrument. The instrument triggers on the rising edge of this input. The input impedance of this input is 1 k. (Depending on the length of cable attached to this input, and the sourc e driving it, it may be desirable to add a coaxial 50 Ohm terminator to this input to pr ovide a proper transmission line termination. The Pasternack (www.pasternack.co m) PE6008-50 BNC feed-thru 50 Ohm terminator is suggested for this purpose .) When the MODE switch (item 8) is set to the “INT” position, this connec tor is used as an output that generates a 200 ns wide TTL-level pulse for each trig ger event. This output can be used to trigger an oscilloscope, or other test equip ment. The __________________________________________________________________ 9 separation between the main output pulse and the TRIG output pulse is c ontrolled by the DELAY controls and the ADVANCE/DELAY switch (item 8). For this o utput to operate correctly, the delay setting must be less than the period. 5. F REQUENCY Control . This one-turn control varies the center frequency of the main output. 6. A MP Control . The output pulse amplitude is controlled by means of th is one-turn dial over the range of approximately 150 volts to 400 volts. 7. O UT . The is the main output connector. A 50 Ohm load is required for proper operation. 8. I NT/EXT/MAN Mode Switch . With this switch in the INT position, th e repetition rate of the unit is controlled by an internal oscillator, which in turn is c ontrolled by the REPETITION RATE controls. With the switch in the EXT position, the uni t requires a 50 ns (or wider) TTL level pulse applied at the TRIG input in order t o trigger the output stages. For a single pulse output, the switch should be in the “MAN” position and then push the SINGLE PULSE pushbutton (9). The PULSE DELAY controls (item 9) and DELAY MODE switch (item 8) affect the operation of this output. When the DELAY MODE switch is in the “Main Ou t Delayed” position, the pulses on the main output (item 18) and the four logic outputs (items 11-14) are delayed relative to the SYNC OUT pulse by a time cont rolled by the PULSE DELAY controls (item 9). When the DELAY MODE switch is in the “Main Out Advanced” position, the pulses on the main output (item 18) and the four logic outputs (items 11-14) a re advanced relative to the SYNC OUT pulse by a time controlled by the PULSE DELAY controls (item 9). When the DELAY MODE switch is in the “Double Pulse” position, the SYNC OUT pulse is approximately coincident with the first pulse of the pair of p ulses on the main output. For this output to operate correctly, the delay setting must be less th an the period. 9. S INGLE PULSE Pushbutton . When the INT/EXT/MAN switch is in the “MAN” position, the instrument can be triggered by pressing this pushbutton. A single pulse is generated for each button press. __________________________________________________________________ 10 REAR PANEL CONTROLS 1. A C POWER INPUT . A three-pronged recessed male connector is provided o n the back panel for AC power connection to the instrument. Also contained in this assembly is a slow-blow fuse and a removable card that can be removed a nd repositioned to switch between 120V AC in and 240V AC in. For AC line voltages of 110-120V, the power selector card should be ins talled so that the “120” marking is visible from the rear of the instrument. For AC line voltages of 220-240V, the power selector card should be ins talled so that the “240” marking is visible from the rear of the instrument. If it is not set for the proper voltage, remove the fuse and then grasp the card with a pair of pliers and remove it. Rotate horizontally through 180 degrees. Reinstall the card and the correct fuse. In the 120V setting, a 0.5A slow blow fuse is required. In the 240V set ting, a 0.25A slow blow fuse is required. See the “Installation” section for more det ails. __________________________________________________________________ 11 GENERAL INFORMATION BASIC TEST ARRANGEMENT The AVB2-TC-C should be tested with a sampling oscilloscope with a band width of at least 1 GHz to properly observe the high-speed waveform. A typical test arrangement is shown below: AVTECH SAMPLING MONOCYCLE OSCILLOSCOPE GENERATOR BW > 1 GHz MAIN OUTPUT 50 OHM INPUT CONNECTOR 60 dB 120/240V attenuator 50-60 Hz TRIG TRIG CONNECTOR CONNECTOR 20 dB attenuator ALL CABLES: 50 OHM COAXIAL The attenuators are required to prevent damage to the sampling oscillos cope. A 60 dB attenuator with sufficient voltage rating should be used on the main ou tput. The output frequency is controlled by the front panel one-turn FREQUENC Y control. Clockwise rotation of the control increases the frequency of the output monocycle (or decreases the pulse width of the output waveform). The output pulse amplitude is controlled by means of the one turn poten tiometer (AMP). The output amplitude may be varied from about 150 to 400 Volts peak to peak. For lower output amplitudes (and for lower spurious at reduced amplitudes) it is recommended that external attenuators be used. __________________________________________________________________ 12 MINIMIZING WAVEFORM DISTORTIONS U SE 50  TRANSMISSION LINES AND LOADS Connect the load to the pulse generator with 50 transmission lines (e. g. RG-58 or RG- 174 cable). This instrument requires a 50 load for proper operation. It will not p roperly drive a high-impedance load. The output stage will be damaged if it is operated into an open circuit (or any other high impedance). Failures due to improper output loading are not covered by the warranty. USE LOW-INDUCTANCE LOADS Lenz’s Law predicts that for an inductive voltage spike will be generat ed when the current through an inductance changes. Specifically, VSPIKE = L  dILOA D/dt, where L is the inductance, ILOAD is the load current change, and t is time. For th is reason, it is important to keep any parasitic in the load low. This means keeping wir ing short, and using low inductance components. In particular, wire-wound resistors sh ould be avoided. PREVENTING DAMAGE The AVB2-TC-C may fail if triggered at a PRF greater than 20 kHz. This unit is designed to operate into a load impedance of 50 Ohms and t he output stage will be damaged if it is operated into an open circuit (or any other hi gh impedance). Failures due to improper output loading are not covered by the warranty . The lifetime of the switching elements in the pulse generator module is proportional to the running time of the instrument. For this reason the prime power to the instrument should be turned off when the instrument is not in use. __________________________________________________________________ 13 OPTIONS The AVB2-TC-C is available with these options: -OS OPTION This option allows an externally generated DC offset to be added to the output. The desired DC offset is applied to the back panel OS terminal, which is co nnected to the output centre conductor trhough a high-quality RF inductor. Do not exc eed 50V, 250 mA. -EA OPTION To control the output amplitude with an external voltage, set the rear- panel switch to the “EXT” position and apply 0 to +10V to connector A (RIN  10k). -EF OPTION To control the output center frequency with an external voltage, set th e rear-panel switch to the “EXT” position and apply 0 to +10V to connector F (RIN  10k). __________________________________________________________________ 14 MECHANICAL INFORMATION TOP COVER REMOVAL The interior of the instrument may be accessed by removing the four Phi llips screws on the top panel. With the four screws removed, the top cover may be slid back (and off). ELECTROMAGNETIC INTERFERENCE To prevent electromagnetic interference with other equipment, all used outputs should be connected to shielded 50 loads using shielded 50 coaxial ca bles. Unused outputs should be terminated with shielded 50 BNC terminators or with shielded BNC dust caps, to prevent unintentional electromagnetic radiation. All cord s and cables should be less than 3m in length. __________________________________________________________________ 15 POWER SUPPLY AND FUSE REPLACEMENT This instrument has three main fuses, plus two spares. One, which prote cts the AC input, is located in the rear-panel power entry module, as described in the “Rear Panel Controls” section of this manual. If the power appears to have failed, check the AC fuse first. The other two fuses (plus two spares) are located on the internal DC po wer supply, as shown below: Negative Power spare OK LED fuses Negative DC fuse Positive Positive DC fuse Power OK LED The positive fuse and one of the spare fuses on this circuit board are 1A slow-blow fuses, Littlefuse part number R452001. (This fuse can be ordered from D igikey, www.digikey.com. The Digikey part number is F1343CT-ND). The negative f use and the second spare fuse are 0.5A slow-blow fuses (Littlefuse R452.500, Di gikey part number F1341CT-ND). If you suspect that the DC fuses are blown, follow this procedure: 1. Remove the top cover, by removing the four Phillips screws on the to p cover and then sliding the cover back and off. __________________________________________________________________ 16 2. Locate the two “Power OK” LEDs on the power supply circuit board, as illustrated above. 3. Turn on the instrument. 4. Observe the “Power OK” LEDs. If the fuses are not blown, the two LED s will be lit (bright red). If one of the LEDs is not lit, the fuse next to it ha s blown. 5. Turn off the instrument. 6. If a fuse is blown, use needle-nose pliers to remove the blown fuse from its surface-mount holder. 7. Replace the fuse. (Spare 1 Amp and 0.5 Amp fuses are provided on the circuit board. They may be transferred to the active fuse locations using needl e-nose pliers.) __________________________________________________________________ 17 PERFORMANCE CHECK SHEET __________________________________________________________________ Document Outline * [1]WARRANTY * [2]TECHNICAL SUPPORT * [3]TABLE OF CONTENTS * [4]INTRODUCTION + [5]AVAILABLE OPTIONS * [6]SPECIFICATIONS * [7]INSTALLATION + [8]VISUAL CHECK + [9]PLUGGING IN THE INSTRUMENT * [10]FRONT PANEL CONTROLS * [11]REAR PANEL CONTROLS * [12]GENERAL INFORMATION + [13]BASIC TEST ARRANGEMENT * [14]MINIMIZING WAVEFORM DISTORTIONS + [15]USE 50 TRANSMISSION LINES AND LOADS + [16]USE LOW-INDUCTANCE LOADS * [17]PREVENTING DAMAGE * [18]OPTIONS + [19]-OS OPTION + [20]-EA OPTION + [21]-EF OPTION * [22]MECHANICAL INFORMATION + [23]TOP COVER REMOVAL + [24]ELECTROMAGNETIC INTERFERENCE * [25]POWER SUPPLY AND FUSE REPLACEMENT * [26]PERFORMANCE CHECK SHEET __________________________________________________________________ References 1. file:///root/tmp.html#2 2. file:///root/tmp.html#2 3. file:///root/tmp.html#3 4. file:///root/tmp.html#4 5. file:///root/tmp.html#4 6. file:///root/tmp.html#5 7. file:///root/tmp.html#6 8. file:///root/tmp.html#6 9. file:///root/tmp.html#6 10. file:///root/tmp.html#8 11. file:///root/tmp.html#10 12. file:///root/tmp.html#11 13. file:///root/tmp.html#11 14. file:///root/tmp.html#12 15. file:///root/tmp.html#12 16. file:///root/tmp.html#12 17. file:///root/tmp.html#12 18. file:///root/tmp.html#13 19. file:///root/tmp.html#13 20. file:///root/tmp.html#13 21. file:///root/tmp.html#13 22. file:///root/tmp.html#14 23. file:///root/tmp.html#14 24. file:///root/tmp.html#14 25. file:///root/tmp.html#15 26. file:///root/tmp.html#17