Sine wave antisipator circuit

Sounds dangerous to me. Wonder how "accurate" the OP's 90° of "lag" really is? ...Jim Thompson

An opamp integrator will give you a pretty-much constant 90 degree phase lag. Then go into the comparator, and use whichever edge you like.

John

You could read your "Art of Electronics" by Horowitz and (Winfield) Hill (ISBN: 0-52137095-7) which talks about "phase-sequence filters" at Figure 5.41 where a six-section network gives +/-0.5 degree error over a 100:1 frequency change.

The circuit was developed for single-side-band radio.It does involve a fair number of components, and getting accurate sets of four each of C, C/2, C/4 and C/8 capacitances might be a bit of a pain, but the concept is remarkably simple.

-- Bill Sloman, Nijmegen

Larkin won't show you anything... he's "laughter intolerant" ;-) ...Jim Thompson

After posting this message I went to Wiki-pedia and found a simple ALL Pass filter which has fixed 180d phase shift plus an added 0 to

-180d that can be trimmed, so I set it to 90d +180d =3D270d. Simple and trimable. Finally know what an "All Pass Filter" is used for! Your interger plus comparator is do-able but less trimable.

Thanks all, Harry

You need a sim to prove that an integrator will add 90 degrees of lag to a sine wave?

In real life, with a moderate-GBW opamp and a real comparator, namely affordable parts, one might expect some error from exactly 90 degrees. So some tweaks, and simulations, might be appropriate.

If it's his comparator that has the 90 degree lag (and that's not entirely clear to me) maybe he just needs a faster comparator.

John

As a practical matter, the integrator would need some degeneration on the DC gain (like another R across the C), otherwise it would integrate the offset voltage and stop working pretty fast.

Too bad you can't just buy a Hilbert transformer from Digikey.

Best regards, Spehro Pefhany

Of course.

You can, and they'll deliver it 12 billion years before they get the order.

John

Use a 4X pll followed by a walking ring counter.

You need a simulation to understand what an integrator does?

John

"antisipator"

Sounds like "anti-sipator"

So funny.

ANTICIPATE

ANTICIPATOR

I anticipated you being nailed for spelling much earlier than this...

Not sure if I homed in right, but I found a neat one:

Much better, considering the analog source.

Could design a fiber optic solution too.

All depends on the degree of precision you are after.

You say you want no delay, but then you go on to say....

...you want added delay...And what makes you think a 90o phase advance 'antisipator' is for rookies, it is all waveform processing, and that is your 'no delay' solution if there is one.

More irrationality...and if +/- 20 % affects the so-called 90o delay by more than 5% , you have other things going on- transport delay perhaps- not in a wired system.