Stanford Research Systems SR844, User Manual

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1-20 Aux Outputs and Inputs
SR844 RF Lock-In Amplifier
9 Use the knob to adjust AUX OUT 1 to
-6.500 V. The CH1 display should now read close to
-6.500 V.
Besides reading basic DC voltages, the Aux In voltages may be used to normalize the signal. In Ratio
mode, the X
and Y signals are multiplied by (1.000V/AUX IN 1) or (1.000V/AUX IN 2) prior to time
constant filtering. Ratio mode is fully explained in Chapter 3, CH 1 Display and Output .
Another application of the AUX IN voltages is to provide a second demodulation, sometimes known as
the
Double Lock-In Technique . This is described in Chapter 2.
The displays may be stored in the internal data buffers at a programmable sampling rate. This allows
storage of not only the lock-in outputs (X, Y, R or
θ
) but also the values of the AUX IN voltages. See
Chapter 4, Data Storage , for more information.