Field effect transistor modulator circuit

Claim 1

A modulator circuit comprising: a first and second field effect transistor each having a first gate electrode, a second gate electrode, a drain electrode and a source electrode, the source electrodes of said transistors being connected together at a point of reference potential; a first biasing means connected to the drain electrode of each transistor; a second biasing means, including a source of potential and a variable resistor, connected to the second gate electrode of each transistor for providing substantially linear resistive operation of each transistor; a first transformer having a primary and a secondary winding, one end of the secondary winding of said first transformer being connected to the first gate electrode of the first transistor, the other end of the secondary winding of said first transformer being connected to the first gate electrode of the second transistor, one end of the primary winding of the first transformer being connected to said point of reference potential; means for applying a first signal between the ends of the primary winding of said first transformer; means including a capacitor for simultaneously coupling a second signal to the second gate electrode of each device; a second transformer having a primary and a secondary winding, one end of the secondary winding of said second transformer being connected to said point of reference potential; means including a first coupling capacitor for connecting one end of the primary winding of said second transformer to the drain electrode of said first transistor; means including a second coupling capacitor for connecting the other end of the primary winding of said second transformer to the drain electrode of said second transistor; and a pair of output terminals connected to the ends of the secondaRy winding of the second transformer for providing an output signal.