SRS Labs SR850 - Manual (Page 225)

7-7
Performance Tests
2. DC Offset
This test measures the DC offset of the input.
Setup
Connect a 50
Ω
terminator to the A input. This shorts the input so the lock-in's own DC offset will be
measured.
Procedure
1) {PRESET} (Turn the lock-in off and on with the [
←
] key pressed)
2) Press the keys in the following sequence:
[REF/PHASE]
<Ref. Frequency>
[1] [ENTER]
[GAIN/TC]
<Sensitivity>
Use the knob to select 1 mV.
[DISPLAY/SCALE]
<Type and Trace>
Highlight the trace number.
Use the knob to select trace 3 (R) for the top display.
3) Wait at least 10 seconds, then record the reading of R.
4) Press
[INPUT]
<Coupling>
Select DC coupling.
5) Wait 10 secONDS, then record the reading of R.
6) This completes the DC offset test. Enter the results of this test in the test record at the end of this
section.