Ref Out Amplitude - Stanford Research Systems SR844 User Manual

5. Ref Out Amplitude

This test measures the amplitude and frequency response of the front panel REF OUT signal.
Setup
We will use the SR844 to measure the REF OUT signal amplitude. Connect the REF OUT to the SIGNAL
IN with a cable. The REF OUT signal is nominally a square wave with amplitude 1.0 Vpp into 50
high frequencies, the waveform becomes more sinusoidal leading to a change in the amplitude of the
fundamental (as measured by the SR844) at higher frequencies.
Procedure
1) Press Shift then Recall to restore the factory preset instrument settings.
2) Press the keys in the following sequence:
CH1 Display twice
Set the CH1 display to R[dBm].
3) REF OUT amplitude 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) Use the knob to set the reference frequency (Reference display) to the value 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) This completes the Ref Out Amplitude test. Enter the results of this test in the test record at the
end of this chapter.
Performance Tests 5-13
SR844 RF Lock-In Amplifier
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