Feature filtering - The digital enhancement and suppression of periodic waveforms
Abstract
The possibility of enhancing or suppressing a repetitive waveform of known period but unspecified shape by means of digital techniques is examined. A digital filter for feature enhancement is described, which is capable of enhancing any repetitive input signal of period equal to six times the sample spacing, since its major passbands align exactly with the signal's various harmonic components; the signal will maintain its shape because the passbands are identical and the filter has a linear phase response. The output of such a digital filter may be subtracted from that of an allpass network with the same peak gain and transmission delay to produce feature suppression. Another feature suppression approach is outlined, which uses integer arithmetic, has a somewhat smaller effective settling time for a given performance and gives perfect feature suppression in the sense that it introduces no computational round-off errors.
- Publication:
-
Electronics Letters
- Pub Date:
- March 1977
- DOI:
- 10.1049/el:19770159
- Bibcode:
- 1977ElL....13..220L
- Keywords:
-
- Digital Filters;
- Frequency Response;
- Microwave Filters;
- Signal Processing;
- Signal To Noise Ratios;
- Waveforms;
- Digital Techniques;
- Steady State;
- Transfer Functions;
- Weighting Functions;
- Communications and Radar