SRS Labs SR850 - Manual (Page 237)

7-19
Performance Tests
8. Sine Output Amplitude Accuracy and Flatness
This test measures the amplitude accuracy and frequency response of the internal oscillator Sine Out.
Setup
We will use the lock-in to measure the Sine Out. Connect the Sine Out to the A input of the lock-in.
Procedure
1) {PRESET} (Turn the lock-in off and on with the [
←
] key pressed)
2) Press the keys in the following sequence:
[DISPLAY/SCALE]
<Type and Trace>
Highlight the trace number.
Use the knob to select trace 3 (R) for the top display.
3) Amplitude accuracy is verified at 1 kHz using various sensitivities. For each sine amplitude and sensi-
tivity setting in the table below, perform steps 3a through 3b.
Sensitivity Sine Output Amplitude
1 V 1.000 Vrms
200 mV 0.200 Vrms
50 mV 0.050 Vrms
10 mV 0.010 Vrms
a) Press
[REF/PHASE]
<Sine Output>
Enter the sine amplitude from the table.
[GAIN/TC]
<Sensitivity>
Use the knob to select the sensitivity from the table.
b) Wait for the R reading to stabilize. Record the value of R.
c) Repeat 3a and 3b for each amplitude in the table.
4) Frequency response is checked at frequencies above 1 kHz. The sine amplitude is set to 1 Vrms for
all frequencies. The test frequencies are listed below.
Test Frequencies
24 kHz
48 kHz
72 kHz
96 kHz