Patent US6097773A successfully refreshed from Google Patents.
US6097773A
Expired / Lapsed
US
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Co-channel interference reduction
Assignee: Microsoft Technology Licensing LLC
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Filing: 1997-08-28
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Granted: 2000-08-01
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Expires: 2017-08-28
Abstract
Abstract Co-channel interference in an AMPS (Advanced Mobile Phone System) receiver, having at least two diversity paths each for producing a received signal, is reduced by determining weights for combining the received signals in dependence upon the received signals and a reference signal, combining the received signals in accordance with the determined weights to produce a combined received signal, demodulating the combined received signal, and producing the reference signal by amplitude limiting the combined received signal or modulating the demodulated signal or a signal derived from the demodulated signal, so that the reference signal is produced from the combined received signal with amplitude variations reduced and with frequency variations of the desired signal substantially maintained.
Inventors
- 👤 Alan J. A. Carter
- 👤 Derek Hilborn
- 👤 Norman P. Secord
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 11:39
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/02; H04B7/04; H04B7/08; H04B7/0837; H04B7/0842; H04B7/0848; H04B7/0851
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
89 words
A method of reducing co-channel interference in a receiver having at least two diversity paths each for producing a frequency modulated received signal, comprising the steps of: determining weights for combining the received signals in dependence upon the received signals and a reference signal; combining the received signals in accordance with the determined weights to produce a combined received signal; demodulating the combined received signal to produce a demodulated signal; filtering the demodulated signal to produce a filtered signal; and modulating the filtered signal to produce the reference signal.
Claim 2
Independent Claim
89 words
A method of reducing co-channel interference in a receiver having at least two diversity paths each for producing a frequency modulated received signal, comprising the steps of: determining weights for combining the received signals in dependence upon the received signals and a reference signal; combining the received signals in accordance with the determined weights to produce a combined received signal; demodulating the combined received signal to produce a demodulated signal; filtering the demodulated signal to produce a filtered signal; and modulating the filtered signal to produce the reference signal.
Claim 3
Dependent Claim
68 words
A method as claimed in claim 1 wherein the step of filtering the demodulated signal comprises the steps of producing a first signal having reduced signal components in a predetermined frequency band, producing a second signal having signal components only in a narrow frequency band within the predetermined frequency band and identifying a desired received signal, and combining the first and second signals to produce the filtered signal.
Claim 4
Dependent Claim
26 words
A method as claimed in claim 2 wherein the step of producing the second signal comprises frequency tracking said signal components identifying the desired received signal.
Claim 5
Dependent Claim
23 words
A method as claimed in claim 3 and including the step of monitoring energy of said signal components identifying the desired received signal.
Claim 6
Dependent Claim
18 words
A method as claimed in claim 3 wherein the receiver comprises an AMPS (Advanced Mobile Phone System) receiver.
Claim 7
Dependent Claim
133 words
Apparatus comprising: a receiver having at least two diversity paths each for producing a frequency modulated received signal; a weight calculation unit for determining weights for combining the received signals in dependence upon the received signals and a reference signal; a signal combiner for combining the received signals in accordance with the determined weights to produce a combined received signal; a demodulator for demodulating the combined received signal to produce a demodulated signal; and means for reducing amplitude variations of the combined received signal to produce the reference signal; wherein the means for reducing amplitude variations of the combined received signal to produce the reference signal comprises a filter for filtering the demodulated signal to produce a filtered signal, and a modulator for frequency modulating the filtered signal to produce the reference signal.
Claim 8
Dependent Claim
133 words
Apparatus comprising: a receiver having at least two diversity paths each for producing a frequency modulated received signal; a weight calculation unit for determining weights for combining the received signals in dependence upon the received signals and a reference signal; a signal combiner for combining the received signals in accordance with the determined weights to produce a combined received signal; a demodulator for demodulating the combined received signal to produce a demodulated signal; and means for reducing amplitude variations of the combined received signal to produce the reference signal; wherein the means for reducing amplitude variations of the combined received signal to produce the reference signal comprises a filter for filtering the demodulated signal to produce a filtered signal, and a modulator for frequency modulating the filtered signal to produce the reference signal.
Claim 9
Dependent Claim
70 words
Apparatus as claimed in claim 6 wherein the filter comprises a first filter for producing a first signal having reduced signal components in a predetermined frequency band, a second filter for producing a second signal having signal components only in a narrow frequency band within the predetermined frequency band and identifying a desired received signal, and a combiner for combining the first and second signals to produce the filtered signal.
Claim 10
Dependent Claim
26 words
Apparatus as claimed in claim 7 wherein the second filter comprises a frequency tracking unit for frequency tracking said signal components identifying the desired received signal.
Claim 11
Dependent Claim
22 words
Apparatus as claimed in claim 8 and comprising a unit for monitoring energy of said signal components identifying the desired received signal.
Claim 12
Dependent Claim
22 words
Apparatus as claimed in claim 7 and comprising a unit for monitoring energy of said signal components identifying the desired received signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-08-01 | 2004-01-31 | 2004-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-08-01 | 2008-01-31 | 2008-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-08-01 | 2012-01-31 | 2012-08-01 | $7700.00 | Window Closed / Lapsed |