alternate active all-pass

** The "spherical chickens in a vacuum" joke from the Big Bang Theory is a lot funnier.

..... Phil

I always heard that with engineers, not physicists.

The old ones are the best, of course.

Nowadays though would we even bother. Do everything with DSP where possible unless the frequency is beyond it.

We're doing an all analog I/Q modulator box to simulate an eddy-current transducer, 1-30 MHz range. It's a starter project for a new engineer.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

well let him figure out what all-pass filter to use then, mr. mom!!!

Certain Parties talked me into using wideband all-pass shifters and some other cute tricks. It was pretty much a disaster. So on Friday we decided to go maximally simple and just get it done.

I hate it when we mess up the rev A board. Well, it was his first project, with a lot to learn.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

Since the active all-passer only needs a fast buffer and it sees a purely resistive Z at it's non-inverting terminal a current-feedback amp might be a better choice

Lots of phase-shifting circuits "in the literature" (this is circa

1950.) Hey a circular sweep generator have him design one of those! Sounds like fun!