Teledyne LeCroy AP033 - Manual (Page 36)

AP033 Active Differential Probe
30 922260-00 Rev A
2. Carefully move the AP033 probe head from the Differential Drive No Termination connector of
the AP033/AP034 Calibration Fixture to the Differential Drive 50 Ohm Termination connector.
Make sure that the probe is fully engaged in the fixture.
3. Set the oscilloscope to display channel 1.Set Coupling to DC 1 MΩ, and Global BWL to Off.
Autobalance the AP033 by pressing the AUTOBALANCE button twice. Set the oscilloscope
trigger mode to AUTO.
4. If necessary, center the trace with the Probe Offset (or Channel O
FFSET
) knob.
5. Connect the output of the leveled sine wave generator to the Differential Drive 50 Ohm
Termination connector of the AP033/AP034 Calibration Fixture. If using a model SG504
generator, insert a ÷2 50Ω BNC attenuator between the generator output and the test fixture
input.
6. Set the leveled sine wave generator frequency to 50 kHz, and the amplitude to approximately
300 mVp-p. When using a model SG504 generator, set the output to 0.6V pk-pk at the output
which will correspond to 300 mV at the output of the ÷2 attenuator.
7. Set the oscilloscope vertical scale factor to 50 mV/div and the horizontal scale factor to 10
μsec/div. Set the Trigger source to Channel 1. Adjust the trigger level for a stable display. Turn
on Math Channel A. Press MATH SETUP, then REDEFINE A. Set the A Math type to Average, Avg
Type to Continuous, with 1:15 weighting, of channel 1. Turn off the trace 1 display.
8. Adjust the output amplitude of the leveled sine wave generator for a display of exactly 6
divisions (300 mV) peak to peak.
9. Change the leveled sine wave generator frequency to 250 MHz, taking care not to change the
output amplitude.
10. Change the oscilloscope horizontal scale to 1 ns/div. In the SETUP TIMEBASE menu, select RIS
Sampling. If necessary, turn the channel 1 display back on and adjust the trigger for a stable
trace. Once a stable trace has been achieved, turn off the channel 1 trace to only display the
averaged waveform.
11. Measure the peak-to-peak output amplitude of the AP033. Record the reading to two-digit
resolution (xx0 mV) as ‘Probe Output Voltage at 250 MHz’ in the Test Record.
12. Divide the measured output amplitude recorded in step B-11 by 300 mV. Record the answer to
two-digit resolution (0.xx) in the Test Record. This is the ‘Differential Mode Gain at 250 MHz’.
13. Move the leveled sine wave generator output cable from the Differential Drive 50 Ohm
Termination connector of the AP033/AP034 Calibration Fixture to the channel 2 input of the
oscilloscope.