Removing low frequency interference in a digital FM receiver

Details Removing low frequency interference in a digital FM receiver Removing low frequency interference in a digital FM receiver

1994-11-28

1997-10-21

Marcelo, Melvin

Pulse or digital communications

Receivers

Interference or noise reduction

375254, 375340, 375350, 455309, 329341, 371 51, 371 377, H03D 1300, H04L 2206

Patent

active

056804180

ABSTRACT:
In a digital FM receiver having a demodulator that receives a radio signal and generates therefrom a phase sample whose behavior determines an output of the demodulator, an apparatus for removing a low-frequency interference signal from the phase sample converts the phase sample into a frequency sample which is then high-pass filtered to produce a filtered frequency sample. The filtered frequency sample is then converted into a filtered phase sample, which may be further demodulated in accordance with known techniques. Converting the phase sample into a frequency sample may be performed by a first order difference circuit. Converting the filtered frequency sample into the filtered phase sample may be performed by an integrator. Because the demodulator may produce degraded performance when the inventive apparatus is applied to a radio signal that does not have low-frequency interference, in another aspect of the invention the demodulator is further provided with a circuit for detecting the presence of the low-frequency interference signal in the radio signal, and alternatively selecting, in response thereto, either the filtered or original phase sample to be supplied to further demodulation circuitry.

REFERENCES:
patent: 3593150 (1971-07-01), Michishita et al.
patent: 4380082 (1983-04-01), Namiki
patent: 4501004 (1985-02-01), Yoshida et al.
patent: 4575862 (1986-03-01), Tahara et al.
patent: 4803701 (1989-02-01), Rhodes
patent: 4908581 (1990-03-01), Honjo
patent: 4995104 (1991-02-01), Gitlin
patent: 5283815 (1994-02-01), Chennakeshu et al.
patent: 5339456 (1994-08-01), Dickerson

Affiliated with

Also associated with

Rating

Removing low frequency interference in a digital FM receiver does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Removing low frequency interference in a digital FM receiver, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Removing low frequency interference in a digital FM receiver will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1012869