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Calibration
Users can perform two types of calibrations: DC offset trim and AC gain adjustments.
To trim DC offset, all connections must be disconnected from the input and the outputs ports.
On the front panel, simply press and hold the input coupling button while at GND. Release the
button when calibration starts as display indicates “CAL” and counts down to completion with
“End” displayed. DC offset trimming can also be performed through the remote commands.
Commands are listed in the remote interface section below.
For accurate calibration, power on the SR446 and wait for least 20 minutes to ensure it is warm
up.
AC gain calibration compare output signal with respect to input signal at a given frequency. One
recommendation is to use lock-in amplifier like SR865A. (
Basic procedures:
1.
Set and measure the reference signal source. Derive expected output readings for each
channel.
2.
Measure the outputs of the SR446
3.
Adjust the trim pots in the unit to match the expected readings for each channel.
SR446 Gain Calibration Setup
50
Ω
Source
settings
Output
reading
Save
Recall
Offset
knob
