Title:
METHOD FOR DETECTING INPUT SIGNAL FREQUENCY WITH ADAPTABILITY AND ADAPTIVE INFINITE IMPULSE RESPONSE FILTER
Document Type and Number:
Japanese Patent JPH09307402
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To make the filter adaptive by specifying a digital filter algorithm so as to allow a noise frequency to approach a concerned signal frequency in the case that the remarkably high level noise is in existence in a signal channel. SOLUTION: An input signal is sampled at a prescribed rate and a sequence of numerals nearly proportional to a value of the input signal is processed by a digital filter algorithm. The algorithm as above has a parameter selected so that the filter has at least a zero (point) of a Z plane placed on a unit circle of the Z plane at a radiation angle with respect to a reference axis corresponding to a related frequency, and the filter has at least a pole of the Z plane placed along a radius with respect to the zero of the Z plane deviated from the origin of the Z plane in the unit circle. The zero of the Z plane is shifted along the circumference of the unit circle corresponding to a prescribed frequency band and the presence of a concerned frequency in the frequency band is detected so as to allow the filter to be adaptive a change in the concerned frequency.
Inventors:
AARON MAIKERU CHIESHIA
KAARU JIEROOMU MEI
KAARU JIEROOMU MEI
Application Number:
JP3009897A
Publication Date:
November 28, 1997
Filing Date:
February 14, 1997
Export Citation:
Assignee:
LUCENT TECHNOLOGIES INC
International Classes:
G01H17/00; H03H17/04; H03H21/00; H04L27/26; H04L27/30; H04M1/50; H04Q1/45; (IPC1-7): H03H17/04; G01H17/00; H03H21/00; H04L27/26; H04M1/50; H04Q1/45
Attorney, Agent or Firm:
三俣 弘文
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