[sdiy] passive ring modulator transformers

[Neil Johnson]

Hi Ritchie,

> My point was that his two cases of a gain of +1 and -1 are just the saturated gains.

This Minicircuits document: https://www.minicircuits.com/app/AN00-011.pdf
would seem to disagree with you:

Q. I am a digital designer, dealing with pulses rather than sine
waves. Is it necessary to
furnish only sine waves to a double-balanced mixer?
A.
No. A double-balanced mixer operates as a switching device; pulses are
fine, and may
even reduce distortion.

> The diode mixer or ring modulator is a proportional device, and in fact Minicircuits even recommend a sinusoidal local oscillator signal at +7dBm level for optimum operation. With harder LO drive the behaviour is less linear and tends more towards the saturated switching behaviour, with the addition of a whole load more distortion products in the output.

The +7dBm (level 7 device) spec is to do with conversion gain or loss,
not about driving the diodes.  Other mixers are designed to be run at
higher levels, upto +27dBm for some devices (they tend to be rather
more esoteric!).

> Yes, that dafx paper is the one I was thinking about. Thanks for the links! I only skimmed over it but it looked good.

Hmmm...

Cheers,
Neil
--
http://www.njohnson.co.uk