[Lowfer] TAG in PSKAM10 Mode

[John Andrews]

Ed,

>A block diagram would be a good start as I have build a number of 90�
differential phase shifters and understand the design. What did you use
for balanced modulators and what kind of RF phase shifter did you use to
get the two reference signals?<

I used SBL-3's as balanced modulators. A fine choice, but you're stuck with
50 ohm ports.

The RF phase shift was done with a +45 degree RC combination into one opamp,
and a -45 degree RC into another. Trimmer caps allow precise adjustment. The
opamps are LM6182's which are available, but unfortunately discontinued.
That's a current-feedback opamp that is happy with low impedance loads. I
drove the SBL-3 inputs through 50 ohm series resistors.

I may have some time to sketch this out over the weekend.

John A.