Teledyne LeCroy DXC100A - Manual (Page 8)

DXC100A Differential Probe Pair
6 922259-00 Rev A
Once you are accustomed to making these adjustments, they become quick and
easy. Part 2 can be attempted when high slew rates (>1V/ns) are encountered,
and/or when high frequency (time constraints less than 20ns and frequencies
greater than 1MHz) CMRR is especially important.
Note: Do not change any of the adjustments associated with the +INPUT. Doing
so requires checking the changed adjustment, and perhaps doing the entire Full
Calibration Procedure.
Refer to Figure 1, The DXC100A Board Layout for the location of adjustments,
and to the schematic diagram in Figure 2, The DXC100A Schematic for guidance.
Both figures can be found at the end of this manual.
Part 1
1. Set the oscilloscope sweep speed to 10μs/div. Connect both probe tips
to the same point in the circuit where a measurement is to be made,
and set the DA1855A GAIN, ATTENUATOR and INPUT COUPLING controls
to the same settings to be used in the measurement. Be sure the signal
used does not exceed the maximum common mode voltage allowed
(e.g., 155 volts with 10X and DA1855A ATTENUATOR set to X1).
2. Set the DXC100A to 10X. Adjust C8 (-X10 LF) so as to minimize the total
deflection.
3. Set the DXC100A to 100X. Adjust C18 (-X100 LF1) so as to minimize the
total deflection.
Part 2
4. Set the oscilloscope sweep speed to 20ns/div. Now, set the DXC100A
ATTENUATION to X10. Adjust R2 (-X10 HF1) and R8 (-X10 HF2) so as to
minimize the total deflection.
5. Set the DX100A ATTENUATION to 100X. Adjust R18 (-X100 HF1) so as to
minimize the total deflection.