On Wed, 01 Jul 2009 14:25:07 -0700, Joel Koltner wrote:

Would anyone happen to know how a chip like this one:
http://cds.linear.com/docs/Datasheet/5598f.pdf ...manages to generate an
internal 90 degree phase shift from an LO input over the very wide range
of 5MHz-1600MHz? The data sheet says it uses a "poly-phase phase
shifter." I'm guessing... some adjustable analog phase shifters (that
can provide up to 90 degrees of phase shift at 5MHz) that are controlled
by a feedback loop that's looking to null the product of the LO and the
(ostensibly 90 degree shifted) LO?

Seems like this is a bit easier to work with than chips that require 2x
or 4x inputs to generate their 90 degree LO shifts!

Anyone have a favorite IQ modulator that'll work on 2m (and perhaps 70cm
too)? The data sheet's detail of "industry standard pin-out" would
suggest that there are others...

When you find out, let us know...


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