| 摘要 |
The object of the invention is a filter for digital signals which can be operated as a high-pass, low-pass, band-pass or band-stop filter by applying binary signals. It contains inter alia a frequency difference detector, to which not only the signal frequency but also a reference frequency is to be fed, and a counting circuit, preferably a shift register, in which the slope gradient of the filter can be adjusted by applying a binary number 2<n>. Apart from the counting circuit, only NAND and NOR elements are used as components, so that the filter can be integrated without difficulty in a space-saving manner.
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