[sdiy] SSM2164 Balanced Modulator

[Stewart Pye]

If one wanted to build a balanced modulator using an SSM2164, would I be 
correct in assuming that you'd use two linearised VCA circuits, one of 
which has an op amp inverter added to the front of it. The outputs of 
the two VCA's would be mixed using a virtual earth summer. The X input 
would go to both VCA audio inputs (one via the inverter). The Y input 
would go to two precision half wave rectifiers, one negative and one 
positive. The output of the negative half wave rectifier would be 
inverted so that it outputs a positive voltage and sent to the control 
input of the VCA that has the inverter on the audio input. The output of 
the positive rectifier will go to the control input of the other VCA.


When the Y input becomes positive it turns on the VCA to pass the non 
inverted signal. When Y becomes negative it turns on the VCA to pass the 
inverted signal.
It seems to me that this would achieve the desired function. Any thoughts?

Regards,
Stewart.