Dear Andy, LF Group,
To generate linear phase shift, how about a PWM:
Generate a sawtooth at carrier frequency, feed into one input of a
comparator. Other comparator input is analogue "phase" signal.
The higher the "phase" voltage, the later in the cycle the
comparator changes state, ie more phase lag. You could get a
square wave back again by dividing by 2; this would also limit the
phase shift to 180 degrees, which is probably what you want.
Main problem might be that you would have to design the circuit so
that a transition would definitely occur somewhere on the cycle,
whatever the analogue input voltage was - otherwise you would
lose the carrier altogether.
Cheers, Jim Moritz
73 de M0BMU
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