SRS Labs SR850 - Manual (Page 229)

7-11
Performance Tests
4. Amplitude Accuracy and Flatness
This test measures the amplitude accuracy and frequency response.
Setup
We will use the frequency synthesizer to provide an accurate frequency and the AC calibrator to provide a
sine wave with an exact amplitude.
Connect the output of the frequency synthesizer to the phase lock input of the calibrator. Connect the output
of the AC calibrator to the A input of the lock-in. Be sure to use the appropriate terminations where required.
Connect the TTL SYNC output of the synthesizer to the Reference Input of the lock-in.
Set the Synthesizer to: Set the AC Calibrator to:
Function Sine Frequency 1 kHz
Frequency 1 kHz Amplitude 1.000 Vrms
Amplitude 0.5 Vrms Voltage Off
Offset off or 0V Phase Lock On
Sweep off Sense Internal
Modulation none
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. Source>
Use the knob to select External.
<Ref. Slope>
Select Rising edge.
[DISPLAY/SCALE]
<Type and Trace>
Highlight the trace number.
Use the knob to select trace 3 (R) for the top display.
[GAIN/TC]
<Filter db/oct>
Select 24 dB/oct.
3) Amplitude accuracy is verified at 1 kHz and various sensitivities. For each sensitivity setting in the
table below, perform steps 3a through 3c.
Sensitivity AC Calibrator Amplitude
1 V 1.0000 Vrms
200 mV 200.00 mVrms
100 mV 100.000 mVrms
20 mV 20.000 mVrms
10 mV 10.000 mVrms