Demodulation output

This note describes how to output the demodulated signal on the analog output for the Model 9210 lock-in amplifier measurement system.

Outputting the demodulated signal is a tree step process utilizing the the systems flexible function generation capabilities. In the first step, the special function variables Offset 6 and/or Offset 7 are set to the X, Y or DC component of one of the 10 voltage/5 current signals and one of the two lock-in sets. Furthermore the gain of the parameter can be set:

Offset configuration

In the second step, a function is defined using the Offset parameter. By setting the amplitude to zero and Offset 6 or Offset 7 as parameter, the configured function effectively follows the demodulated signal. Any Type, Frequency etc. can be used as long as the amplitude is zero. In the following example, Function 1 uses Offset 6 and Amplitude 1. Amplitude 1 is 0V.

Configuring a function with the offset

In the third step, one of the five outputs A-E (depending on the number of installed modules) is configured to output the configured function. Fx selects the configured function, and type needs to be set to Fx to use a single function. By setting Type to Fx*Fy and configuring Fy as a sine function, it is also possible to generate an amplitude modulated signal at a different frequency than the original input signal. The output range must be sufficiently large for the expected signal, and the output needs to be enabled.

Selecting the output function