[Radio Wrangler]

If you're doing a VCO and are looking for best RX performance, a trick is to do the VCO for double the frequency you first thought of, and use a logic divide by two. This can give a more symmetrical waveform to the mixer and give you an extra dB or so on TOI.

Having a symmetrical mixer driver with long-tailed pairs that apply a current squarewave to a diode ring mixer transformer is another step along this route.

I used to work with Hugh Walker ("Sources of intermodulation distortion in diode ring mixers" Proc. IRE in the early seventies) and I picked up a few tricks.

David