Stanford Research Systems SR865A, Руководство по эксплуатации

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188 Performance Tests Appendix G
SR865A DSP Lock-in Amplifier
Amplitude Accuracy and Flatness
This test measures the amplitude accuracy and frequency response.
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 50
Ω
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.
Preliminary calculations
i) Refer to the Reading values recorded for the Sine Output Amplitude and Flatness test.
ii) Results labeled (A) through (J) are used to set performance Lower Limits and Upper Limits for
Amplitude Accuracy and Flatness
iii) On the Performance Test Record, for Lower and Upper limits, perform the multiplication
indicated with the referenced value of Sine Output Amplitude and Flatness. For example:
Assume result (A) is recorded as 0.4966 V
The Lower Limit at 1V will be 0.99×(
A
)= 0.99×0.4966 V = 0.4916 V
The Upper Limit at 1V will be 1.01×(
A
)= 1.01×0.4966 V = 0.5016 V
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) Amplitude accuracy is verified at 1 kHz and various sensitivities. For each input range setting in
the table below, perform steps 3a through 3c.
Sine Out Amplitude Input Range Sensitivity
1.0000 Vrms 1 V 1 V
300.00 mVrms 300 mV 200 mV
100.000 mVrms 100 mV 100 mV
30.000 mVrms 30 mV 50 mV
10.000 mVrms 10 mV 10 mV