Method and circuit for frequency and phase slaving of a local quartzless oscillator in television

In accordance with the present invention, the circuit for slaving, to a colour television signal, the frequency and phase of an oscillator provided with a frequency and phase control input comprises a quartzless oscillator 10, a phase comparator 7 comparing the output from the oscillator with the modulated chrominance signal U, a multiplier 12 multiplying the error signal arising from the phase comparator by the sign of the chrominance signal B-Y set to a fixed value during the burst selection pulse and a conventional servocontrol loop applying the corrected error signal to the control input 2 of the oscillator 7. The invention is used in PAL television chrominance decoders. CONFORMEMENT A LA PRESENTE INVENTION, LE CIRCUIT D'ASSERVISSEMENT EN FREQUENCE ET EN PHASE SUR UN SIGNAL DE TELEVISION COULEUR D'UN OSCILLATEUR MUNI D'UNE ENTREE DE COMMANDE DE FREQUENCE ET DE PHASE COMPREND UN OSCILLATEUR SANS QUARTZ 10, UN COMPARATEUR DE PHASE 7 COMPARANT LA SORTIE DE L'OSCILLATEUR AU SIGNAL DE CHROMINANCE MODULE U, UN MULTIPLICATEUR 12 MULTIPLIANT LE SIGNAL D'ERREUR ISSU DU COMPARATEUR DE PHASE PAR LE SIGNE DU SIGNAL DE CHROMINANCE B-Y FORCE A UNE VALEUR FIXE PENDANT L'IMPULSION DE SELECTION DE SALVE ET UNE BOUCLE D'ASSERVISSEMENT CLASSIQUE APPLIQUANT LE SIGNAL D'ERREUR CORRIGE A L'ENTREE DE COMMANDE 2 DE L'OSCILLATEUR 7.L'INVENTION EST UTILISEE DANS LES DECODEURS DE CHROMINANCE DE TELEVISION PAL.