Color identification and associated apparatus in sequential color television systems

Claim 1

A COLOR TELEVISION RECEIVER ADAPTED FOR OPERATING WITH A COMPOSITE SIGNAL ELABORATED IN A TRANSMITTER, SAID COMPOSITE SIGNAL COMPRISING A WIDE-BAND PICTURE SIGNAL, SYNCHRONIZING SIGNALS AND AN AUXILIARY WAVE MODULATED IN TIME DIVISION BY TWO COLOR SIGNALS AND BY AT LEAST ONE OTHER SIGNAL, REFERRED TO AS A CHANNEL IDENTIFYING SIGNAL; SAID COLOR SIGNALS AND SAID IDENTIFYING SIGNAL BEING, IN SAID TRANSMITTER, DIRECTED TO A COMMON CHANNEL BY MEANS OF A SWITCHING SYSTEM HAVING A FIRST AND A SECOND INPUT TO WHICH SAID COLOUR SIGNALS ARE RESPECTIVELY APPLIED DURING THE VISIBLE PORTIONS OF THE FIELDS AND TO ONE OF WHICH SAID IDENTIFYING SIGNAL IS APPLIED DURING RECURRENT TIME INTERVALS, REFERRED TO AS CHECKING PERIODS, EACH OF WHICH OCCURS WITHIN A VERTICAL BLANKING INTERVAL; SAID SWITCHING SYSTEM HAVING A FIRST STATE IN WHICH IT CONNECTS SAID OUTPUT TO SAIR FIRST INPUT AND A SECOND STATE IN WHICH IT CONNECTS SAID OUTPUT TO SAID SECOND INPUT, AND BEING ACTUATED TO PASS OVER REGULARLY, AT THE LINE FREQUENCY, FROM ONE STATE TO THE OTHER, AT LEAST BETWEEN THE BEGINNING OF EACH OF SAID CHECKING PERIODS AND THE BEGINNING OF THE VERTICAL BLANKING INTERVAL COMPRISING THE NEXT CHECKING PERIOD, SAID RECEIVER COMPRISING: MEANS FOR SEPARATING SAID SYNCHRONIZING SIGNALS AND SAID AUXILIARY WAVE FROM SAID COMPOSITE SIGNAL; A SYNCHRONIZING AND SWEEP CIRCUIT; AN AUXILIARY CHANNEL HAVING AN INPUT AND AT LEAST ONE OUTPUT: MEANS FOR APPLYING SAID SYNCHRONIZING SIGNALS AND SAID AUXILIARY WAVE RESPECTIVELY TO SAID SYNCHRONIZING AND SWEEP CIRCUIT AND TO SAID AUXILIARY CHANNEL INPUT; A SWITCH HAVING AT LEAST ONE INPUT COUPLED TO SAID AUXILIARY CHANNEL OUTPUT, AND AT LEAST ONE OUTPUT; SAID SWITCH HAVING A FIRST STATE IN WHCH IT CONNECTS SAID SWITCH OUTPUT TO SAID SWITCH INPUT AND A SECOND STATE IN WHICH IT DISCONNECTS SAID SWITCH OUTPUT FROM SAID SWITCH INPUT; SAID SWITCH BEING SAID TO HAVE A CORRECT PHASE OR A WRONG PHASE ACCORDING TO WHETHER ITS FIRST AND SECOND STATES RESPECTIVELY COINCIDE IN TIME WITH THE FIRST AND SECOND STATES OF SAID TRANSMITTER SWITCHING SYSTEM OR NOT; A CHANNEL, REFERRED TO AS A CHECKED CHANNEL, HAVING AN INPUT COUPLED TO SAID SWITCH OUTPUT, WHEREBY, DURING SAID CHECKING PERIODS, A SIGNAL, REFERRED TO AS A TEST SIGNAL, PROPAGATES THEREIN, WHICH INDICATES WHETHER THE PHASE OF SAID SWITCH IS CORRECT OR WRONG; AND A SWITCH CONTROL CIRCUIT HAVING A FIRST INPUT COUPLED TO SAID SYNCHRONIZING AND SWEEP CIRCUIT FOR RECEIVING THEREFROM PULSES AT THE LINE FREQUENCY, AND A SECOND INPUT COUPLED TO SAID CHECKED CHANNEL, AT LEAST DURING SAID CHECKING PERIODS, FOR CAUSING SAID SWITCH TO PASS OVER REGULARLY, AT THE LINE FREQUENCY, FROM ONE STATE TO THE OTHER, OUTSIDE OF SAID CHECKING PERIODS, AND MEANS, CONTROLLED BY SAID TEST SIGNAL, FOR, DURING SAID CHECKING PERIODS, MAINTAINING OR ALTERING THE REGULAR ALTERNATION, AT THE LINE FREQUENCY, OF THE STATES OF SAID SWITCH, IN ACCORDANCE WITH A CHARACTERISTIC OF SAID TEST SIGNAL.