Anyone have any favorite circuits for accomplishing a variable phase shift which is relatively independent of frequency? What I'd like: o Logic level input; logic level output o Input is square wave between about 2MHz and 120MHz o Output is two channels, same frequency as input, whose relative phase may be adjusted over 360 degrees minimum (-180 to +180 OK too; just need 360 span) o Output same logic levels as input, nominally. o Ideally, the phase will be controlled through an analog voltage input, say 0-5V, but could be different.
It's obviously relatively easy to generate variable delays which are essentially independent of frequency, but the resulting phase shifts then depend linearly on frequency. I'd like the phase shift to be nearly independent of frequency. You can also pretty easily make phase shift networks that provide a constant frequency-independent relative phase shift between two channels, but I need the phase shift to be controllable. I have some ideas about how to do this, but figured there may be some standard easy way that I'm missing.