Explanation
Why Phase Correction of the Probe Is Necessary
The probe comes with its phase corrected approximately to match the input capacitance
of the relevant measuring instrument. However, there is some error in the input resistance
and input capacitance of each input channel of individual measuring instruments. This
results in a mismatch in the voltage divider ratio between low and high frequency signals
and causes uneven frequency characteristics.
The probe is equipped with a variable capacitor used to adjust the voltage divider ratio
(trimmer) for high frequency signals. This trimmer is used to correct the phase so that
even frequency characteristics are obtained.
When using a probe for the first time, make sure to perform phase correction.
Because the input capacitance varies on each channel, probe compensation is also
required when the probe is switched from one channel to another.
Phase Compensation Signal
The probe compensation signal output terminal delivers the following rectangular wave
signal.
Frequency: Approx. 1 kHz
Amplitude: Approx. 1 V
Differences in the Waveform Caused by the Phase Correction of the Probe
Correct waveform
Over compensated
(the gain in the high
frequency region is up)
Under compensated
(the gain in the high
frequency region is low)
Precautions to Be Taken When Using a Probe on the Frequency Module
(701281 (FREQ) and 720281 (FREQ))
You cannot perform phase correction of the probe on the frequency module. Perform
phase correction of the probe on another module before connecting the probe to the
frequency module for use.
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IM 720120-01E
3.6 Compensating the Probe (Phase Correction)