LeCroy AP034, Instruction Manual

Page: 36 / 76

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ISSUED: January 2000 AP034-OM-E Rev D
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6. Using the alligator clips on the end of the interconnect cable,
connect the signal source ground to the square pin on the
Attenuator Adapter’s “–“ input. Attach the signal output to the
square pin on the Attenuator Adapter’s “+” input.
7. Turn on the test oscilloscope. The EFFECTIVE GAIN
indicator for
÷
10 or
÷
20 should be lit. (NOTE: If the X1
EFFECTIVE GAIN indicator is lit instead of the
÷
10 or
÷
20
indicator, make sure that the plug-on adapter installed on the
probe tip is the Attenuator, and not the AC Coupler.)
8. Set the test oscilloscope Volts/Div to 200 mV (for LeCroy
oscilloscopes with ProBus) or 20 mV/Div when using the
ADPPS with an oscilloscope without scale factor correction;
5
µ
s/Div; AUTO trigger mode; Trigger source: External. Set
the Bandwidth Limiting to 20–30 MHz and Average the
waveform 1:31 to reduce noise.
9. Turn on the signal source. Set the output frequency to
approximately 5 kHz. Set the output amplitude to
approximately 1 V for matching the ÷10 Attenuator Adapter,
or 2 V for matching the ÷20 Attenuator Adapter.
10. Adjust the test oscilloscope trigger level for a stable trace. If
necessary, use the probe offset to position the waveform to
show the square corner of the test signal. NOTE: Do not use
the oscilloscope offset or position controls to reposition the
trace. Many of the signal generators used for compensation
calibration only have square corners on one of the two edges
of the output waveform. (Rising or falling edge, but not both.)
Be sure to display the correct edge for this step.
11. Using the square adjustment tool, adjust the +LF Comp (See
Figure 8) to achieve the best square corner and flat top of the
displayed waveform. Note that the added capacitance of the
adjustment tool may change the compensation of the
waveform when it is inserted. The correct adjustment is
achieved when the best corner is displayed with the
adjustment tool removed.