Unusual quadrature phase shifter

[Dan Slater]

Don Tillman wrote:
> 
> For those of you into 90-degree phase shift networks for frequency
> shifters and the like, check out the latest EDN magazine, June 5, the
> Ideas For Design section, page 111.
> 
> I've never seen a phase shifter circuit like this before.  Some sort
> of quadruple helix thing.  It's weird as all hell.
> 

Definitely a weird circuit, It is also described in the classic book,
the "Art of Electronics" 2nd Edition on page 295. This circuit has the
advantage of circuit symmetry but appears not to be very efficient in
terms of parts count, at least as compared to the more conventional Dome
filter designs. It also seems like it would be hard to trim this design
to compensate for component tolerances, etc.

Dan Slater (dslater at ix.netcom.com)