Stanford Research Systems SR844, User Manual

Page: 152 / 246

5-8 Performance Tests
SR844 RF Lock-In Amplifier
Wide Reserve Down
Select
LOW NOISE
Wide Reserve.
Close Resrv
once
Select
LOW NOISE
Close Reserve.
Sensitivity Down
once
Select 300 mV sensitivity.
3) Amplitude response is checked at various frequencies. For each frequency in the table below,
perform steps 3.1 through 3.2.
Test Frequencies
100 kHz
300 kHz
1 MHz
3 MHz
10 MHz
30 MHz
100 MHz
200 MHz
3.1) Set the RF synthesizer to the frequency in the table.
3.2) Wait for the SR844
UNLOCK
indicator to turn off.
3.3) Wait for the CH1 reading to stabilize. Record the CH1 reading (dBm).
4) Add one 20 dB attenuator at the SIGNAL IN. The total attenuation at the SIGNAL IN is now
-23 dB. Press the following key sequence:
Sensitivity Down twice
Select
30 mV
sensitivity.
5) Repeat step 3 at this sensitivity.
6) Add another 20 dB attenuator at the SIGNAL IN. The total attenuation at the SIGNAL IN is now -
43 dB. Press the following key sequence:
Sensitivity Down twice
Select 3 mV sensitivity.
7) Repeat step 3 at this sensitivity.
8) This completes the amplitude response test. Enter the results of this test into the test record at the
end of this chapter.