Push-pull modulator circuit with means to vary the output level of the carrier and sidebands

Claim 1

A TRANSMITTED-CARRIER PUSH-PULL MODULATOR CIRCUIT COMPRISING TWO JUNCTION TRANSISTORS EACH HAVING EMITTER, BASE AND COLLECTOR ELECTRODES, FIRST AND SECOND SUPPLY LINES, MEANS TO MAINTAIN A UNIDIRECTIONAL POTENTIAL DIFFERENCE BETWEEN SAID SUPPLY LINES, MEANS CONNECTING THE EMITTER ELECTRODES OF SAID TRANSISTORS, TO A COMMON POINT, MEANS INCLUDING FIRST VARIABLE RESISTANCE MEANS CONNECTING SAID COMMON POINT TO THE FIRST OF SAID SUPPLY LINES, MEANS TO PROVIDE DIRECT CURRENT CONNECTIONS BETWEEN THE COLLECTOR ELECTRODES OF SAID TRANSISTORS AND THE SECOND OF SAID SUPPLY LINES, MEANS TO SUPPLY CARRIER SIGNALS IN OPPOSITE PHASE TO THE BASE ELECTRODES OF SAID TRANSISTORS, MEANS INCLUDING SECOND VARIABLE RESISTANCE MEANS TO VARY THE CURRENT THROUGH SAID FIRST VARIABLE RESISTANCE MEANS IN DEPENDENCE UPON A MODULATING SIGNAL, AND MEANS TO DERIVE AN OUTPUT SIGNAL FROM THE COLLECTOR CIRCUITS OF SAID TRANSISTORS, IN OPERATION THE AMPLITUDE OF THE CARRIER SIGNALS BEING SUFFICIENTLY HIGH TO BIAS OFF EACH OF THE TRANSISTORS IN TURN, THE ARRANGEMENT ENABLING ADJUSTMENT OF THE MEAN LEVEL OF THE OUTPUT SIGNAL AND OF THE MODULATION DEPTH TO BE EFFECTED BY CHANGING THE VALUES OF THE FIRST AND SECOND VARIABLE RESISTORS RESPECTIVELY.