U.S. Philips Corporation

Kurt-Joachim Johannes

Walter H Demmer

Otto L Warmuth

Rolf-Dieter Gutsmann

Detlef Deutschmann

The invention relates to a digital low-pass filter which effects a frequency reduction by a factor which is equal to the ratio w/2 between the frequency of the input signal and the frequency of the output signal, wherein w is an odd integer. The input signal is applied to m series-arranged registers. The input signal of the first and the output signals of all the registers are multiplied by coefficients. A change-over switch precedes an input of each multiplier, the change-over switch switching the coefficients symmetrically. The switching instants are always symmetrical relative to a reference sampling instant. The filter is particularly suitable for use in video signal processing, to reduce negative influences of an analog-to-digital converter.

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Hamburg, Germany

Kurt-Joachim Johannes