lecroy AP034-OM-E-06 电路图.pdf

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1、AP034-OM-E Rev DISSUED: January 2000? ? ? This procedure can be used to verify the warranted characteristics of the AP034 Active Differential Probe. The recommended calibration interval for the model AP034 Active Differential Probe is one year. The complete performance verification procedure should

2、be performed as the first step of annual calibration. You can record test results on a photocopy of the Test Record provided at the end of this section. You can do the performance verification without removing the instrument covers, exposing yourself to hazardous voltages. Adjustment should only be

3、attempted if a parameter measured in the Performance Verification Procedure is outside of the specified limits. Adjustment should only be performed by qualified personnel. TEST EQUIPMENT REQUIRED Table 3 lists the test equipment and accessories (or their equivalents) that are required to verify the

4、performance of the AP034 Active Differential Probe. This procedure is designed to minimize the number of calibrated test instruments required. Only the parameters listed in boldface in the “Minimum Requirements” column must be calibrated to the accuracy indicated. Because the input and output connec

5、tor types may vary on different brands and models of test instruments, additional adapters or cables may be required. RadioFans.CN 收音机爱 好者资料库 ?ISSUED: January 2000AP034-OM-E Rev D ? TABLE 3. List of Required Equipment DescriptionMinimum RequirementsTest Equipment Examples Wide Band Oscilloscope 1Min

6、imum 1 GHz bandwidth 2 mV to 5 V scale factors ProBus interface equipped 2% vertical accuracy LeCroy LC584A Digital MultimeterDC: 0.1% accuracy AC: 0.2% accuracy to measure 200 mV and 2 V rms 1 kHz 5 digit resolution Agilent Technologies 34401A Fluke 8842A-09 Keithley 2001 Function GeneratorSine Wav

7、e and Square Wave output waveforms 20 Vp-p? 70 Hz to 10 MHz frequency range Agilent Technologies 33120A Stanford Research Model DS340 Leader LAG-120B High Frequency Sine Wave Generator 50 to 500 MHz and 50 kHz Output adjustable from 300 mV to 2 Vp-p Agilent Technologies 8648C Terminator, in-line, BN

8、C? ?Pomona 4119-50 Terminator, precision, BNC? 0.2%LeCroy TERM-CF01 Attenuator, BNC? ?10 (20 dB)Pomona 4108-20dB BNC coaxial cable (2 required) ? ?Pomona 5697-36 Calibration FixtureProBus Extension CableLeCroy PROBUS-CF01 Calibration FixtureAP033/AP034 Calibration FixtureLeCroy AP03x-CF01 Banana Plu

9、g adapterBNC female-to-banana plugPomona 1269 Notes 1 If a LeCroy ProBus equipped oscilloscope is not available, you may use an alternate oscilloscope that meets the other minimum specifications listed, and the model ADPPS power supply, to perform the adjustment procedure. The input RadioFans.CN 收音机

10、爱 好者资料库 AP034-OM-E Rev DISSUED: January 2000? ? ? ?!? offset or position must remain at center screen. PRELIMINARY PROCEDURE 1. Connect the AP034 Active Differential Probe to the female end of the ProBus Extension Cable. Connect the male end of the ProBus extension cable to Channel 1 of the oscillos

11、cope. 2. Turn the oscilloscope on and allow at least a 30- minute warm-up time for the AP034 and test equipment before performing the Verification Procedure. 3. Turn on the other test equipment and allow these to warm up for the time period recommended by the manufacturer. 4. While the instruments a

12、re reaching operating temperature, make a photocopy of the Performance Verification Test Record (located at the end of this section), and fill in the necessary information. The warranted characteristics of the AP034 Active Differential Probe are valid at any temperature within the Environmental Char

13、acteristics listed in the Specifications. However, some of the other test equipment used to verify the performance may have environmental limitations required to meet the accuracy needed for the procedure. Make sure that the ambient conditions meet the requirements of all the test instruments used i

14、n this procedure. PROCEDURE Note Correct operation of the AP034 controls requires oscilloscope software version 8.1.0 or higher. The use of earlier versions is not recommended. You can verify the software version in the test oscilloscope by pressing the SHOW STATUS button, then selecting the System

15、menu option. Contact your local LeCroy representative if the software in your oscilloscope requires updating. RadioFans.CN 收音机爱 好者资料库 ?ISSUED: January 2000AP034-OM-E Rev D ? A. Check Gain Accuracy 1. From the oscilloscope display, select the channel that the AP034 is connected to (channel 1), then s

16、elect the “Coupling” menu. Set the Coupling to DC 1 M. (If the only choice available is AC 1 M, remove the Plug-on AC Coupling adapter from the probe tip.) 2. If necessary, set the probe offset to 0.000 V by rotating the OFFSET knob in the CHANNEL section of the oscilloscope. 3. Using a BNC female-t

17、o-female adapter, connect one end of a BNC cable to the probe end of the ProBus Extension ?!?#?$? end of the BNC cable. 4. Connect one end of a second BNC cable to the output of the Function Generator. Attach the BNC-to-dual-male banana plug adapter to the free end of the second BNC cable. Connect t

18、he banana plugs to the Digital Multimeter (DMM). 5. Set the DMM to measure AC Volts. 6. Set the mode of the Function Generator to Sine Wave; the frequency to approximately 1 kHz; and the output amplitude to approximately 200 mV rms, as measured by the DMM. 7. Record the measured amplitude to 100 V r

19、esolution in the Test Record. 8. Unplug the output cable from the DMM. Remove the BNC-to- banana plug adapter from the end of the cable. 9. Autobalance the AP034 by pressing the AUTOBALANCE menu button located in the “Coupling” menu. 10. Carefully align the four pins that correspond to the Different

20、ial Drive No Termination portion of the AP03x- CF01 Calibration Fixture with the input receptacles in the AP034 probe head. Press the probe into the fixture to fully engage the pins. 11. Connect the banana plugs of the precision terminator to the digital multimeter (DMM). AP034-OM-E Rev DISSUED: Jan

21、uary 2000? ? 12. Connect the free end of the output cable from the Function Generator to the Differential Drive No Termination connector of the AP033/AP034 Calibration Fixture. 13. After the DMM reading has stabilized, record the measured output amplitude to 100 V resolution in the Test Record. 14.

22、Divide the measured output voltage (recorded in step A-13) by the sine wave generator output voltage (probe input voltage) from step A-7. Subtract 1.0 from the ratio and multiply the result by 100 to get the error in percent. 1001% = VoltageInput ageutput VoltMeasured O Error 15. Record the answer t

23、o two significant places (x.xx%) on line A-15 in the Test Record. 16. Verify that the X1 gain error is less than 2%. 17. Disconnect both BNC cables from the test setup. B. Check High Frequency Common Mode Rejection Ratio (CMRR) Note Common Mode Rejection Ratio (CMRR) is defined as the Differential M

24、ode Gain divided by the Common Mode Gain (normalized inverse of the Common Mode response). At frequencies below approximately 250 MHz, the bandwidth- related attenuation in the AP034 Active Differential Probe is so insignificant that the Differential Mode Gain can be assumed to be unity (1.0). 1. Di

25、sconnect the ProBus Extension cable from the AP034 and the oscilloscope. Reconnect the AP034 directly to the Channel 1 input of the oscilloscope. 2. Carefully move the AP034 probe head from the Differential Drive No Termination connector of the AP033/AP034 Calibration Fixture to the Common Mode Driv

26、e 50 ohm ?ISSUED: January 2000AP034-OM-E Rev D ? Termination connector. Make sure that the probe is fully engaged in the fixture. 3. Set the oscilloscope to display channel 1. In the oscilloscope Channel 1 “COUPLING” menu, set Coupling to DC 1 M, and Global BWL to Off. Autobalance the AP034 by press

27、ing the AUTOBALANCE menu button twice. Set the oscilloscope trigger mode to AUTO. 4. If necessary, center the trace with the Probe Offset (channel OFFSET knob). 5. Connect a BNC cable from the output of the high frequency sine wave generator to the Channel 2 input of the oscilloscope. 6. Set the osc

28、illoscope as follows: DisplayChannel 2 only Channel 2 VOLTS/DIV0.5 V/div Channel 2 CouplingDC 50 Trigger on2 Trigger coupling 2HF TIME/DIV5 ns/div Acquisition ModeNORMAL 7. Set the high-frequency sine wave generator frequency to 100 MHz, and the amplitude to approximately 2 Vp-p. Set the RF Output t

29、o ON. 8. Adjust the oscilloscope trigger level as needed for a stable display. 9. Adjust the output amplitude of the high frequency sine wave generator for a display of exactly 4 divisions (2 V) peak-to- peak. Turn off the RF Output. 10. Move the high frequency sine wave generator output cable from

30、the oscilloscope channel 2 input to the Common Mode Drive 50 ohm Termination connector of the AP033/AP034 Calibration Fixture. 11. Set the high-frequency sine wave generator RF Output to ON. AP034-OM-E Rev DISSUED: January 2000? ? 12. Set the oscilloscope to display channel 1 only, set the trigger s

31、ource to channel 1, and set the channel 1 vertical scale factor as needed to measure the amplitude of the displayed waveform. Adjust the trigger level as necessary for a stable display. This is the common mode signal. Turn on Math Channel A. Press MATH SETUP, then REDEFINE A. Set the A Math type to

32、Average, Avg Type to Continuous, with 1:15 weighting, of channel 1. Turn off the trace 1 display. Note The amplitude of the Common Mode signal should be relatively small. If the output waveform appears to be a 1 Volt square wave, check that the Common Mode Drive 50 ohm Termination connector of the A

33、P033/AP034 Calibration Fixture is being used and not the Differential Drive 50 ohm Termination connector. 13. Measure the peak-to-peak output amplitude of the AP034. Record the reading to two-digit resolution (xx mV) as “Common Mode Signal at 100 MHz” in the Test Record. 14. Calculate the Common Mod

34、e Rejection Ratio (CMRR) at 100 MHz by dividing 2,000 mV by the measured Common Mode Signal recorded in step B-14 (direct reciprocal of the Common Mode Gain). Record the result to two-digit resolution (xx:1) in the Test Record. 15. Verify that the CMRR at 100 MHz is greater than 18:1 (25 dB). 16. Tu

35、rn off the high frequency sine wave generator RF output, and disconnect the output cables. ?ISSUED: January 2000AP034-OM-E Rev D ? C. Check Low Frequency CMRR Note Because greater amplitudes are required to measure the higher CMRR specifications at low frequencies, the Function Generator will be use

36、d in place of the high-frequency sine wave generator for the low frequency CMRR test. 1. Carefully move the AP034 probe head from the Common Mode Drive 50 ohm Termination connector of the AP033/AP034 Calibration Fixture to the Common Mode Drive No Termination connector. Make that sure the probe is f

37、ully engaged in the fixture. 2. Set the oscilloscope to display channel 2, the channel 2 input coupling to DC1 M, the channel 2 vertical scale to 5 Volt/div, the horizontal scale to 5 ms/div, and the trigger source to channel 2. Set BW limiting on channels 1 and 2 to 25 MHz. 3. Connect the BNC Tee a

38、dapter to the output connector of the Function Generator. Connect a BNC cable from one end of the BNC Tee adapter to channel 2 of the oscilloscope. Connect a second BNC cable from the remaining end of the BNC Tee adapter to the Common Mode Drive No Termination input connector of the AP033/AP034 Cali

39、bration Fixture. Caution Make sure that the Common Mode Drive No Termination connection is used. Prolonged application of the power levels used in the low frequency common mode test may damage the termination resistance in either 50 ohm Termination input of the AP033/AP034 calibration fixture. AP034

40、-OM-E Rev DISSUED: January 2000? ? 4. Set the sine wave generator frequency to 70 Hz, and the output amplitude to 20 Vp-p, (4 divisions on the oscilloscope). If necessary, adjust the trigger level for a stable display. 5. Set the oscilloscope to display channel 1, but leave the trigger source set to

41、 channel 2. Set the vertical scale of channel 1 to 2 mV/div. Create a math waveform on channel A defined as the Average of channel 1. Set the average factor as necessary to reduce noise. Increase the zoom to a factor of four (0.5 mV/division). Turn off the waveform display of all channels except the

42、 A Math waveform. 6. Increase the zoom of the A Math waveform as needed to measure the peak-to-peak amplitude. This is the common mode signal. 7. Record the displayed “Common Mode Signal at 70 Hz” to two-digit resolution (x.xx mV) in the Test Record. 8. Calculate the Common Mode Rejection Ratio (CMR

43、R) at 70 Hz by dividing 20 000 mV by the measured Common Mode Signal recorded in step C-7 (direct reciprocal of the Common Mode Gain). Record the result to two-digit resolution (xx 000:1) in the Test Record. 9. Verify that the “Common Mode Rejection Ratio at 70 Hz” is greater than 10 000:1 (80 dB).

44、10. Change the output amplitude of the Function Generator to approximately 8.0 Vp-p, and the frequency to 1 MHz. 11. Set the oscilloscope to display channel 2 only. Change the horizontal scale factor to 0.5 s/div, and the channel 2 vertical scale to 2 V/div. Turn the BWL on channels 1 and 2 to 200 M

45、Hz. 12. Adjust oscilloscope trigger level as necessary for a stable display. Adjust the Function Generator amplitude as needed to maintain 8.0 Vp-p as measured on channel 2. 13. Turn off the oscilloscope channel 2 display, turn on the display of channel 1 and the A Math waveform (averaged channel 1)

46、. Adjust the scale factor of channel 1 and the Zoom of the A Math waveform as necessary to accurately measure the amplitude of the averaged signal. ?ISSUED: January 2000AP034-OM-E Rev D ? 14. Record the displayed “Common Mode Signal at 1 MHz” to two-digit resolution in the Test Record. 15. Calculate

47、 the “Common Mode Rejection Ratio (CMRR) at 1 MHz” by dividing 8000 mV by the measured Common Mode Signal recorded in step C-14. Record the result in the Test Record. 16. Verify that the Common Mode Rejection Ratio at 1 MHz is greater than 100:1 (40 dB). 17. Remove all cables and test fixtures from

48、the AP034 probe. This completes the Performance Verification of the AP034. Complete and file the results recorded in the AP034 Performance Verification Test Record, as required by your quality procedures. Apply a suitable calibration label to the AP034 housing as required. # # # AP034-OM-E Rev DISSUED: January 2000? ? AP034 Performance Verification Test Record This record can be used to record the results of measurements made during the pe