Frequency synthesis system for multifrequency transmitter-receiver

Claim 1

IN A MULTIPLE CONVERSION TRANSMITTER-RECEIVER HAVING AT LEAST ONE UNIDIRECTIONAL INTERMEDIATE-FREQUENCY AMPLIFIER COMPRISING FIRST AND SECOND OSCILLATOR MEANS, A FIRST PAIR OF FREQUENCY MIXERS, EACH HAVING ONE INPUT ALTERNATELY CONNECTABLE TO SAID FIRST OSCILLATOR MEANS, AND A SECOND PAIR OF FREQUENCY MIXERS, EACH HAVING ONE INPUT ALTERNATELY CONNECTABLE TO SAID SECOND OSCILLATOR MEANS, THE FIRST MIXER OF EACH PAIR HETERODYNING THE RECEIVER SIGNAL, THE OTHER MIXER IN EACH PAIR HETERODYNING THE TRANSMITTER FREQUENCY, THE OUTPUT OF SAID INTERMEDIATEFREQUENCY AMPLIFIER BEING CONNECTED IN COMMON TO THE OTHER INPUT OF THE TRANSMITTER MIXER IN SAID FIRST PAIR AND TO THE OTHER INPUT OF SAID RECEIVER MIXER IN SAID SECOND PAIR, AND THE INPUT OF SAID INTERMEDIATE-FREQUENCY AMPLIFIER BEING CONNECTED IN COMMON TO THE OUTPUT OF SAID RECEIVER MIXER IN SAID FIRST PAIR AND THE OUTPUT OF SAID TRANSMITTER MIXER IN SAID SECOND PAIR, WHEREBY SAID INTERMEDIATE-FREQUENCY AMPLIFIER IS COMMON TO SAID TRANSMIT AND RECEIVE FUNCTIONS.