Measure Phase Shift

Hello,

By "analog," do you mean a circuit with passive components and chips such as op-amps, etc? On this particular forum, SigmaDSPs and SigmaStudio, we normally solve such a problem with one of the SigmaDSPs, which we would configure using SigmaStudio, a free download. It may be possible, for example, to program a ADAU1701 to perform such a function. The -1701 is analog in, analog out so it appears much like an analog circuit to your application. I could imagine several methods to evaluate phase shift between two input signals, depending upon what your needs are. Thus these questions:

Are your input signals sine waves or something else?

What amplitude is expected at the signal inputs? Fixed or variable, over what range?

What range of phase shift is required -- does one of the signals always lead, or could either one lead?

What are the accuracy requirement?

In the case of fixed amplitude inputs, you could input these into a four-quadrant analog multiplier and lowpass filter. This would provide a maximum positive output for in-phase signals, zero for + or - 90 degrees shift, and maximum negative for 180 degrees. With sine wave inputs, your phase output would be proportional to the cosine of the phase angle. Square wave inputs would result in an output linearly related to phase.

A SigmaDSP could perform this method as well as compensate for a moderate range of signal amplitudes. You could instead implement with it a scheme based upon counting time between zero crossings of the input signals should that be more appropriate for your application.

Best regards,

Bob