Phase shifter question

The phase shifter that exists shifts the phase later with higher frequencies. Later in phase is minus values of degrees. The phase goes from 0 to -180 as frequency increases.

The phase shifter you want poses a bit of a problem. It requires that the phase go earlier with higher frequencies. Over a limited band this can be done but not without also having a variation in gain. This is because, in real life, only information from the past can be used in creation of the output.

Then how about those time machines?

Just invert the output.

John

Or learn to read ?:-)

-180° is _always_ lagging.

...Jim Thompson

Technically that will yield a phase shifter that goes from -180 degrees to -360 -- the endpoints will be right, but if the OP needs a positive slope then he needs to find the contact information for Non-Causal Systems, Inc. to get the parts. (their number is in next year's phone book).

If the OP is referring to H&H figure 2.29, just reverse inputs phi1 and phi2.

Or as I would designate them (as shown in H&H)...

phi1 => +ein

phi2 => -ein

...Jim Thompson

Or he could use those dilithium capacitors that JL figured the guy in the other thread uses.

Ed

Oh, come oh, the digital guys use non-casual filters all the time.

You just to overlook the input-output latency involved and designs can be as non-casual as you'd like. :-)

You'd be lagging at -180=B0 too.=20

--=20 Keith

Yes and no. Let's say you have a differential signal.

in out

• ----C-----+

- ----C----- +

- ----L ---- +

So feed the low frequency with crossed inductors and feed the high frequency is non-crossed capacitors.

Assuming source and load resistors, this should end up as an all-pass network with phase shift.