Combination radio transmitter and receiver

Claim 1

A DUAL PURPOSE STAGE FOR OPERATION AS A MIXER DURING RECEIVER OPERATION AND AS A MODULATOR POWER AMPLIFIER DURING TRANSMITTER OPERATION COMPRISING AMPLIFYING MEANS HAVING INPUT ELECTRODES AND AN OUTPUT ELECTRODE, FIRST MEANS FOR APPLYING A RECEIVED SIGNAL TO AN INPUT ELECTRODE, SECOND MEANS FOR APPLYING A LOCAL OSCILLATOR SIGNAL TO AN INPUT ELECTRODE, THIRD MEANS CONNECTED TO SAID OUTPUT ELECTRODE FOR PRODUCING THE INTERMEDIATE FREQUENCY SIGNAL FORMED BY THE HETERODYNING ACTION OF SAID AMPLIFYING MEANS DURING RECEIVER OPERATION, SAID THIRD MEANS COMPRISING A BRIDGE TYPE PARALLEL RESONANT CIRCUIT FORMED BY TWO CONNECTED CIRCUITS WHICH ARE SERIES RESONANT AT THE INTERMEDIATE FREQUENCY AND A SHORT CIRCUIT BETWEEN THE ENDS OF SAID TWO SERIES RESONANT CIRCUITS, MEANS FOR APPLYING A SPEECH SIGNAL TO BE TRANSMITTED TO ONE OF SAID SERIES RESONANT CIRCUITS OF SAID THIRD MEANS, SAID SPEECH SIGNAL BEING MODULATED BY SAID AMPLIFYING MEANS ON A CARRIER WAVE SIGNAL APPLIED TO AN INPUT ELECTRODE BY SAID SECOND MEANS AND THE MODULATED CARRIER WAVE SIGNAL APPEARING ON SAID FIRST MEANS.