Accession Number : ADD014623

Title :   Tracking Harmonic Notch Filter.

Descriptive Note : Patent, Filed 20 Mar 89, patented 3 Jul 90,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Emo, Frederick L

Report Date : 03 Jul 1990

Pagination or Media Count : 6

Abstract : An electronic filter for automatically tracking and removing harmonically related interfering electrical signals such as power line interference harmonics without attenuating other signals of interest even though the signals are frequency stable and/or near the interference signal frequencies. The filter comprises a very narrow band electronic commutated capacitor-bank comb-notch filter driven by a counter/decoder circuit which is in turn driven by a phase locked loop. The filter also comprises two narrow band analog filters tuned to the two lowest harmonics of the interfering signal and drives the comb-notch at unit multiples of the fundamental of the interference frequency. This action is continuous such that center frequencies of the notches are automatically adjusted to compensate for small variations in the interference frequency. Patents. (rrh)

Descriptors :   *BANDSTOP FILTERS, *ELECTRIC FILTERS, *INTERFERENCE, *PHASE LOCKED SYSTEMS, ELECTRIC POWER, ELECTRICITY, FREQUENCY, HARMONICS, LOOPS, PATENTS, SIGNALS, TRACKING, TRANSMISSION LINES, VARIATIONS

Subject Categories : Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE