Stanford Research Systems SR865A Operation Manual page 208

190 Performance Tests
Amplitude Linearity
This test measures the amplitude linearity. This tests how accurately the lock-in measures a signal smaller
than full scale. This test requires the preceding Sine Output Amplitude Accuracy and Flatness test results
to verify specified performance.
Setup
We will use the internal sine output to provide an accurate sine wave for testing the signal input function.
This test requires the preceding Sine Output Amplitude Accuracy and Flatness test results to verify
specified performance.
Connect the Sine Out+ to the Voltage A input of the SR865A using a 1 meter BNC cable, with the
precision 50Ω terminator at the A input BNC. This test only uses ONE Sine Out BNC. This means that
each measurement will nominally be 50% of the programmed sine amplitude.
Procedure
1) {PRESET} (press [Save Recall], then touch {Recall default}. Touch {Confirm})
2) Use the front panel to make the following adjustments
Touch {Fint} to display the internal frequency keypad
Enter a frequency of 1.0 kHz.
Press Filter [Slope/adv] multiple times
Select 24 dB/oct.
3) For each of the amplitudes listed below, perform steps 3a through 3b.
Sine Out Amplitude
1.0000 Vrms
100.000 mVrms
10.000 mVrms
1.000 mVrms
a) Use the front panel to make the following adjustments
Touch {Ampl} to display the amplitude keypad
Enter the amplitude from the table
Press [Sensitivity Down]
Select the sensitivity from the table.
b) Wait for the R reading to stabilize. Record the value of R.
4) This completes the amplitude linearity test. Enter the results of this test in the test record at the
end of this section.
SR865A DSP Lock-in Amplifier
Sensitivity
1 V
100 mV
10 mV
1 mV
Appendix G