Stanford Research Systems SR865A, Operation Manual

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186 Performance Tests Appendix G
SR865A DSP Lock-in Amplifier
Sine Output Amplitude Accuracy and Flatness
This test measures the amplitude accuracy and frequency flatness of the internal oscillator Sine Out.
These results will also be used next for testing the input Amplitude Accuracy.
Setup
We will use the precision ac multimeter to measure the Sine Out. Connect the Sine Out+ to the ac Volts
input of the voltmeter using a 1 meter BNC cable, with the precision 50
Ω
terminator at the voltmeter
connection . This test only uses ONE Sine Out BNC. This means that each measurement with the ac
voltmeter will nominally be 50% of the programmed sine amplitude.
Set the multimeter for ac volts. If using the model 3458A, it should be configured as:
i) Reset: press (blue shift key) then Reset
ii)
SETACV RNDM: press (blue) “S”, then
3 times, then
Ÿ
, then 2 times, then Enter
iii) ACV: press ACV
iv-a)
for RANGE 1: press (blue) “R”, then “1”, then Enter
iv-b)
for RANGE 0.1: press (blue) “R”, then “0.1”, then Enter
iv-c)
for RANGE 0.01: press (blue) “R”, then “0.01”, then Enter
Procedure
1) {PRESET} (press [Save Recall], then touch {Recall default}. Touch {Confirm})
2) Amplitude accuracy is verified at 1 kHz. Use the front panel to make the following adjustments
Touch {Fint} to display the internal frequency keypad
Enter a frequency of 1.0 kHz.
3) For each sine amplitude, use the voltmeter range setting in the table below, perform steps 3a
through 3b.
Sine Output Amplitude ac voltmeter range
1.00 V 1
300 mV 1
100 mV 0.1
30 mV 0.1
10.0 mV 0.01
1.00 mV 0.01
a) Use the SR865A front panel to make the following adjustments
Touch {Ampl} to display the sine out amplitude keypad
Enter the amplitude from the table.