Abstract: A circuit for generating a control signal includes a frequency-determining element (C3), a clock generator for generating a clock signal and a control circuit coupled to the clock generator for generating a control signal as a function of the magnitude of the voltage at the frequency-determining element and for applying the control signal to the frequency-determining element. The control circuit includes a sawtooth generator having a sawtooth frequency-determining element (C1) for converting the clock signal into a second signal having a constant slope as a function of time, and a storage element (C2) which produces a voltage that depends on the amplitude of the sawtooth signal.

Abstract: Self-adjusting frequency demodulation circuit comprising a frequency demodulator (13) which is designed as an integrated circuit, the adjustment being effected with the aid of a calibration signal source (7) of one single frequency and a measuring circuit (113, 35, 101) coupled to an output (113) of the frequency demodulator (13) by controlling the output signal amplitude of the frequency demodulation circuit with a multiplier (21) which is controllable by the measuring circuit and forms part of a tuning correction circuit which optionally may further include a level shifting circuit (57). The frequency demodulation circuit is particularly suitable for use in a SECAM color television receiver, only one frequency demodulator then being required for demodulating both the two color difference signals and the identification signal.

Abstract: A PAL-NTSC color television standard identification circuit, comprising a first demodulation circuit (7) for a reference component and a second demodulation circuit (11) for a possible color identification component of a color synchronizing signal, can perform a reliable identification by means of a digital decoding circuit (81) for the output signals of the demodulation circuits if the second demodulation circuit (11) is adapted (41, 45, 49) to demodulate along an axis slightly differing from the axis of the color identification component (FIG. 1).