3-8
IM 701510-01E
3.7
Compensating the Probe (Phase Correction)
CAUTION
Never apply an external voltage to the CAL terminal, as damage to the
instrument may result.
Operating Procedure
1.
Turn ON the power switch.
2.
Connect the probe to the input terminal to which the signal is to be applied.
3.
Touch the probe’s tip against the CAL output terminal and connect the grounding wire
to the grounding function terminal.
4.
Press the
AUTO-SETUP key
.
5.
Press the “
EXEC
” soft key. The calibration signal is displayed on the screen.
6.
Insert a screwdriver into the trimmer adjusting hole in the probe and turn the trimmer so
that the displayed waveform becomes square.
Grounding function terminal
CAL signal output terminal
Phase adjusting hole
Explanation
Reason for probe compensation
If the probe’s input capacitance is outside the specified range, the gain will not be constant
across different frequencies, preventing display of the correct waveforms. The input
capacitance varies depending on the probe used, so the variable capacitor (trimmer)
provided on the probe must be adjusted.
Probe compensation must be performed when the probe is to be used for the first time.
Moreover, the appropriate input capacitance varies according to which channel is used, so
probe compensation is required when the probe is switched from one channel to another.
Calibration signal
A CAL signal (square waveform) of the following characteristics is output from the CAL
terminal on the front panel.
Frequency : Approx. 1 kHz
Amplitude : Approx. 1 V
Waveform differences
Correct waveform
Over-compensated
(gain is too high at high
frequency)
Under-compensated
(gain is too low at high
frequency)
