Teledyne LeCroy DXC100A - Manual (Page 13)

Operator’s Manual
922259-00 Rev A 11
6. +Input X10 LF Compensation
NOTE: Low frequency compensation of the DXC100A probe attached to the
+Input is done by observing a small portion of the large amplitude step. With
this magnification, the waveform shows considerable deviation from flat. What
is important is that the front (1μs) and rear (about 10ms) of the waveform are at
the same level.
a. Set the probe to the 10X position.
b. Set the oscilloscope to 10mV/div and 10μs/div.
c. Terminate the pulse generator’s high amplitude output in 50 or
(preferable) 75 Ohms, producing approximately a 5 to 8 volt step.
d. Connect the +probe to the pulse generator’s high amplitude output
using the probe tip to BNC adaptor.
e. Press the X10 Gain button (to invoke AUTOBALANCE).
f. Press the +Input DC button.
g. Connect the pulse generator’s trigger output to the oscilloscope’s
external trigger input and then trigger the oscilloscope on its external
trigger input.
h. Adjust C7 (+X10LF) so the amplitude at the front of the waveform (1μs)
matches the amplitude at the rear of the waveform (10ms using
1ms/div).
7. X10 LF CMRR
a. Continue from the previous step, (using BW Limit set to 20MHz, and the
oscilloscope set to 10mV/div and 10μs/div) connect the +probe and –
probe to the pulse generator output.
b. Press the –Input DC button.
c. Adjust C8 (-X10 LF) capacitor for a minimum amplitude display. The
residual displayed amplitude should be less than 5mV peak (10mV p-p at
slower sweep speeds where the entire waveform is visible). Ignore the
first 1μs after the step (this is adjusted later).