Self-balancing modulator for suppression of carrier wave

Claim 1

A circuit arrangement for modulating a carrier wave with a low frequency signal and preserving the resulting sidebands while suppressing the carrier wave, comprising: a first pair of terminals connectable across a source of carrier wave to be modulated; a second pair of terminals connectable across a source of modulating signal; a third pair of terminals connectable across a load; a fourth pair of terminals connectable across a source of direct current; two transistors of opposite conductivity types each having a base, an emitter with a lead and a collector, the emitter leads of said transistors forming a junction, the emitter-collector paths of said transistors being serially connected across said fourth pair of terminals in aiding relationship; first circuit means coupling said first pair of terminals in push-pull (parallel) to the base-emitter paths of said transistors; second circuit means coupling said second pair of terminals in parallel to the base-emitter paths of said transistors, said second circuit means including capacitive means connected to said junction for differentIally biasing the emitters of said transistors in response to unsymmetrical current flow over said emitter-collector paths; and and third circuit means coupling said third pair of terminals to said emitter-collector paths for balanced energization thereby in the absence of said modulating signal.