Automatic frequency control Automatic scanning over a band of frequencies

HELECTRICITY H03Electronic circuits H03JTUNING RESONANT CIRCUITS SELECTING RESONANT CIRCUITS

H03J7/00Automatic frequency control Automatic scanning over a band of frequencies

H03J7/02Automatic frequency control H03J7/023Neutralization of the automatic frequency correction during a tuning change H03J7/026Means preventing a wrong working of the automatic frequency correction in case of fading or bad signal/noise ratio H03J7/04where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant H03J7/042with reactance tube H03J7/045Modification of automatic frequency control sensitivity or linearising automatic frequency control operation; Modification of the working range H03J7/047Automatic frequency control using an auxiliary signal H03J7/06using counters or frequency dividers H03J7/065the counter or frequency divider being used in a phase locked loop H03J7/08using varactors H03J7/10Modification of automatic frequency control sensitivity or linearising automatic frequency control operation H03J7/12Combination of automatic frequency control voltage with stabilised varactor supply voltage H03J7/14Controlling the magnetic state of inductor cores H03J7/16where the frequency control is accomplished by mechanical means H03J7/18Automatic scanning over a band of frequencies H03J7/183combined with selection between different stations transmitting the same programm H03J7/186using two or more tuners H03J7/20where the scanning is accomplished by varying the electrical characteristics of a non-mechanically adjustable element H03J7/22in which an automatic frequency control circuit is brought into action after the scanning action has been stopped H03J7/24using varactors H03J7/26in which an automatic frequency control circuit is brought into action after the scanning action has been stopped H03J7/28using counters or frequency dividers H03J7/285the counter or frequency divider being used in a phase locked loop H03J7/30where the scanning is accomplished by mechanical means H03J7/305in which an automatic frequency control circuit is brought in action after the scanning action has been stopped H03J7/32with simultaneous display of received frequencies