Abstract: To simplify the apparatus and the method steps to reestablish predetermined phase relationship of a chrominance TV signal with a reference, two chrominance derived signals of carrier frequency, respectively phase shifted by plus and minus 45.degree. with respect to the carrier frequency are obtained; chrominance derived signals, likewise phase shifted with respect to the input chrominance signal, are amplitude modulated with set voltages, and the amplitude modulated chrominance derived signals are so added that the phase position of the resulting chrominance signal will match that of the reference carrier.

Abstract: A circuit for the changeable prolongation of the (phase-) running time of an ultrasound delay line with a delay duration of somewhat less than a line duration for color television signals in the range of the color carrier frequency includes a changeable resistor which is disposed in the signal path and connected to the first input of the ultrasound delay line; a coil which is disposed between the first input of the delay line and the second input which is connected with the reference potential. The coil represents a first winding (8') of a transformer (8), whose second winding (8") is applied at one end thereof on the reference potential, and is connected through a changeable capacity (7) with the connection point of the changeable resistor (6) and an input terminal of a signal to be delayed.

Abstract: A process and two embodiments of an apparatus are disclosed for displaying, on the screen of a conventional home television receiver, curves illustrating analog signal potential functions of the form U(x,y). The process generally requires generating first and second saw-tooth signals synchronized with the vertical and horizontal sync. signals of the picture raster of the home television receiver. At least part of each of the signal potentials U.sub.y and U.sub.x are then compared with the first and second saw-tooth signals to generate first and second impulse signals respectively when equal potential conditions are observed. The first impulse signal is then differentiated with respect to time to form a gate impulse signal of adjustable width for controlling the processing of signal potential U.sub.x. The second impulse signal is differentiated with respect to time to form a brightness control signal for output to the home television receiver.

Abstract: This invention concerns a circuit arrangement for visually representing a horizontal frequency coupled input signal on the picture screen of a video display device such as a domestic television receiver. This is achieved by comparing the input signal to be represented in visual form with a vertical frequency sawtooth signal, the comparison being effected in such manner that a further signal is produced which identifies the moments when the two compared signals are equal. The further signal is then used directly or indirectly to control the brightness of the picture screen of the video display device.The further signal may be a pulse form signal with the leading flanks of the pulses corresponding to moments when the input signal crosses the sawtooth signal upwardly and the trailing flanks corresponding to the moments when the input signal crosses the sawtooth signal downwardly. The further signal is preferably differentiated prior to application to the display device.

Abstract: Correction signals for aperture correction of video signals are generated in such a way that the peak values of the correction signal produced in an aperture corrector which are dependent upon the frequency of the video signal to be corrected are maintained constant.

Abstract: The video signals are applied to a standard aperture correction circuit and also to a non-linear circuit. The output of the non-linear circuit and the output of the standard aperture correction circuit are applied to the two inputs of a modulator whose output is combined in a summing circuit with video signals delayed by a time delay corresponding to the time delay in the non-linear circuit and modulator. In a preferred embodiment the non-linear transfer function corresponds to A.sup.2 -A and is achieved by a double-balanced modulator the DC level at whose inputs is adjusted to yield the desired transfer function.