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IM 701240-01E
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App
Index
Preparations for Measurements
3.8
Compensating the Probe (Phase Correction)
When making measurements using a probe on the following modules, be sure to perform
phase correction of the probe first.
• High-Speed 10 MS/s, 12-Bit Isolation Module:
701250 (HS10M12)
• High-Speed High-Resolution 1 MS/s, 16-Bit Isolation Module: 701251 (HS1M16)
• High-Speed 10 MS/s, 12-Bit Non-Isolation Module:
701255 (NONISO_10M12)
• Acceleration/Voltage Module (with AAF):
701275 (ACCL/VOLT)
• Frequency Module:
701280 (FREQ)
CAUTION
Do not apply external voltage to the probe compensation signal output terminal, as
it may damage the internal circuit.
Procedure
1.
Turn ON the power switch.
2.
Connect the probe to the input terminal to which the signal is to be applied.
3.
Connect the probe’s tip to the probe compensation signal output terminal on the
front panel and connect the earth wire to the functional earth terminal.
4.
Perform auto setup according to the procedure described in section 4.5.
5.
Insert a flat-head screwdriver to the phase correction hole and turn the variable
capacitor to make the displayed waveform a correct rectangular wave.
Functional ground
terminal
Phase adjustment
hole
Probe compensation signal output terminal
Explanation
Necessity of Phase Correction of the Probe
The probe comes with its phase corrected approximately to match the input capacitance
of the relevant oscilloscope. However, there is variance in the input resistance and input
capacitance of each input channel of individual oscilloscopes. This results in a mismatch
in the voltage divider ratio between low and high frequency signals and causes uneven
frequency characteristics.
There is a variable capacitor for adjusting the voltage divider ratio (trimmer) for high
frequency signals on the probe. The phase is corrected by adjusting this trimmer so that
even frequency characteristics are obtained.
When using the 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.