JPS6410783A - Tv synchronizing signal generator - Google Patents

Abstract

PURPOSE:To simplify a horizontal synchronizing signal generator by operating a JK flip-flop by using respective frequency-divided pulses that are obtained in the process of frequency dividing a reference oscillation frequency of 32.4MHz to generate a 33.75KHz horizontal frequency signal. CONSTITUTION:The titled generator is provided with a means 101 to obtain a frequency signal of approximately 32.4MHz, a first frequency division means 102 to frequency- divide to three equal divisions, a second frequency division means 103 which divide an output from the means 102 into four equal divisions in synchronism with the means 102, a third frequency division means 104 which divides an output from the means 103 into four equal divisions in synchronism with the first frequency division means 102, and the JK flip-flop circuits 107B, 108-111 to generate respective pulse signals during a horizontal flyback cycle to which outputs from the respective frequency dividers are inputted. Accordingly, an output from the oscillator 101 is frequency- divided into 48 equal divisions by the frequency dividers 102-104 and comes to be signals of 675KHz each, and in the mean time, is divided into 20 equal divisions by frequency dividers 105, 106 to come to be a horizontal frequency of 33.75KHz. In such a way, respective pulses to be used in generating horizontal synchronizing signals can be obtained without using a delay circuit.