Transceiver modulator-demodulator employing common elements

Claim 1

A MODULATOR-DEMODULATOR OPERATIVE IN A TRANSMIT MODE AND A RECEIVE MODE COMPRISING: FIRST, SECOND AND THIRD SOURCES OF SIGNALS; A PAIR OF BILATERAL CURRENT CONTROL DEVICES EACH BEING OPERATIVE TO MIX SIGNALS FROM AT LEAST TWO OF SAID SOURCES DURING EACH OF SAID MODES OF OPERATION, EACH HAVING A CONTROL ELECTRODE AND A PAIR OF ELECTRODES; MEANS FOR APPLYING SAID FIRST SOURCE SIGNALS TO THE CONTROL ELECTRODE OF BOTH OF SAID CONTROL DEVICES; INPUT CIRCUIT MEANS FOR APPLYING SECOND SOURCE SIGNALS TO AN ELECTRODE OF BOTH OF SAID CONTROL DEVICES; OUTPUT CIRCUIT MEANS CONNECTED TO SAID OTHER ELECTRODE OF BOTH OF SAID CONTROL DEVICES AND SAID THIRD SIGNAL SOURCE; AND, BIASING MEANS INDEPENDNT OF SAID SIGNAL SOURCES FOR BIASING BOTH OF SAID CONTROL DEVICES TO CAUSE BOTH OF SAID DEVICES TO MIX SIGNALS FROM SAID FIRST AND SECOND SOURCES DURING SAID RECEIVE MODE OF OPERATION AND PRODUCE A SUPPRESSED CARRIER SIGNAL IN SAID OUTPUT CIRCUIT, AND FOR REBIASING BOTH OF SAID CONTROL DEVICES TO MIX SIGNALS FROM SAID FIRST AND THIRD SOURCES DURING SAID RECEIVE MODE OF OPERATION AND PRODUCE A PRODUCT DETECTION SIGNAL IN SAID INPUT CIRCUIT.