I would appreciate your clarification regarding the relationship between the readout theta value (in volts) and the phase (in degrees or radians) of lockin amplifier. Specifically:
What is the exact formula to convert the theta voltage reading into phase?
Does this conversion depend on the range of the R-T (Resistance-to-Theta) converter? If so, how?
Hello,
If you define the phase shift as the phase of the input signal with respect to the local oscillator, then the equation is (360 degrees/ 1V) (V_theta)= phi. For example, a phase shift of 90 degrees will result in a 250mV output.
If the incorrect voltage range is selected, this will affect your measurement. The voltage range you select should be based on your I and Q voltage levels
which are where the probe points are. You will want to select the smallest range possible, but not a range that is below your signal. This will result in a clipping of your signal and skew results. If you have any more questions please let me know!
