Stanford Research Systems SR865A, Operation Manual

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Appendix B The FFT Display 165
SR865A DSP Lock-in Amplifier
Touch 3 times to decrease the frequency
scale to 39.06 kHz/div.
Move the cursor back to the peak.
always baseband (i.e. the frequency span starts
at 0 Hz or dc).
The cursor readout now reads 100.098 kHz
because each frequency bin has been reduced to
0.6 kHz.
4. Touch the {Avgs} tile along the bottom to
display the averaging up/down buttons.
Touch twice to increase the number of
averages to 10.
FFT graphs can be averaged to reduce
fluctuations. Averaging is exponential in the
number of averages.
Touch twice to decrease the number of
averages to 1.
Turn the averaging off to speed up the display.
5. Touch the {Live} tile along the bottom to pause
the FFT display.
Touch {Paused} to return to a live display.
The FFT may be paused.
Press the [Time Constant Down] key multiple
times to set the time constant to 1 ms. When the FFT source is set to the PSD output,
the maximum frequency span is set by the time
constant. The shorter the time constant, the
higher the maximum frequency span. This is