Teledyne Lecroy PP008, Руководство оператора, Страница: 12 / 17

PP008 Passive Probe
10
Probe Compensation
Proper compensation of the probe is required to assure good amplitude
accuracy in the dynamic portions of the waveform being measured. LF
compensation matches the probe to differences in oscilloscope input
capacitance. The LF compensation should always be checked and adjusted
as needed when first connecting a passive probe to the oscilloscope input.
HF compensation matches time constants within the probe to compensate
for normal component tolerances. It is typically not necessary to adjust HF
compensation unless the probe is being used with an oscilloscope with large
differences in input characteristics than the oscilloscope model it was
designed for.
LF compensation is performed by connecting the input of the probe to a low
frequency square wave, such as the oscilloscope calibrator signal set to
1 kHz. The compensation is adjusted by rotating the adjustment accessible
through the small hole in the center of the housing near the BNC connector.
Use the tool supplied with the probe for this adjustment.
Undershoot Overshoot Correct adjustment
Should HF compensation be required, access the
adjustments by sliding the black plastic cover off
the compensation housing near the BNC con-
nector. A pulse generator with low overshoot and a
300 ps risetime is the required signal source, along
with a set of attenuators. The probe must be
connected to a terminated probe tip to BNC
adapter.
Some overshoot and ring will be present at some
settings of V/Div. Adjust both trimmers for the
overall best response on all ranges.
Typical optimum HF
adjustment