Stanford Research Systems SR830 Manual page 75

Front Panel
setup the SR830 to measure the input signal.
1.Press [AUTO GAIN] to set the sensitivity.
2.Press [AUTO RESERVE].
3.Adjust the time constant and roll-off until there is no Time Constant
overload.
4.Press [AUTO PHASE] if desired.
5.Repeat if necessary.
At very low frequencies, the auto functions may not function properly.
This is because very low frequency signals overload very infrequently
and the time constants used tend to be very long.
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