Abstract: Digitized FM signals are fed to a sample-and-hold circuit followed by a first sampling stage which is clocked by a second sampling signal whose frequency is an integral multiple of the frequency of a first sampling signal. The output of the first sampling stage is coupled to the input of an interpolating filter which is clocked by the second sampling signal, and whose output is sampled in a second sampling stage clocked by the second sampling signal. The output of the second sampling stage is coupled to the inputs of two zero-crossing detectors each of which drives a group-delay-controlled monostable multivibrator. The output signals of the latter are added with an average-value compensation signal in an adder whose output is sampled in a third sampling stage clocked by the second sampling signal, and fed to a digital conversion filter clocked by the first and second sampling signals and a third sampling signal.

Abstract: In an integrated circuit of a digital peaking filter for the digital luminance channel of a color-television receiver a DC component of the amplitude characteristic independent of the peaking factor is achieved by cascading a first subnetwork and a second subnetwork. The first subnetwork includes a first delay element and an adder at the input end of the digital filter. The output of the adder is coupled to the inputs of second and third delay elements and to the minuend input of a first subtracter. The first subtracter has its output connected to the input of a fourth delay element and to the subtrahend input of a second subtracter. The output of the second subtracter is coupled through a multiplier to the subtrahend input of a third subtracter whose minuend input is connected to the output of the second delay element. The output of the third subtracter is the digital filter output. The peaking factor is applied to the multiplier.

Abstract: A digital filter for the digital luminance channel of a color-television set contains an even number of cascaded delay elements whose junctions as well as the input and the output of the cascade serve as taps. Each of the taps of the half on the input side is connected to an input of a first switch, and each of the taps of the half on the output side is connected to an input of a second switch, such that the two switches are simultaneously set to two taps which are symmetrical with respect to a center tap. The center tap is connected to the first input of a single multiplier, whose second input is fed with a signal corresponding to a constant, and whose output is coupled to the first input of an adder. The output of the first switch and that of the second switch are connected, respectively, to the second and third inputs of the adder, whose output is the output of the subnetwork. Digital filters with at least one such subnetwork can be used as peaking filters in the luminance channel of color-television sets.

Abstract: A digital filter serves to compensate for the reduction in the amplitude of the chrominance-subcarrier reference (fc) caused by the passband of the intermediate frequency stages, and thus to achieve a flat response in the filter's passband within the chrominance-channel bandwidth. The transfer function of the digital filter isY(z)/X(z)=T(z)=1/a+z.sup.-1 +z.sup.-2 /a,where a is a number presettable by the manufacturer of the color-television set but constant in operation.