Patent US5303406A successfully refreshed from Google Patents.
US5303406A
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US
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Noise squelch circuit with adaptive noise shaping
Assignee: Motorola Solutions Inc
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Filing: 1991-04-29
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Granted: 1994-04-12
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Expires: 2011-04-29
Abstract
Abstract A noise squelch circuit for a radio receiver (100) includes an adaptive filter (204) for shaping frequency characteristics of a demodulator out put (115) according to factors which effects squelch sensitivity. Such factors may include channel spacing of the receiver, received signal strength level, received signal deviation, and SINAD. The adaptive filter (204) comprises a switched capacitor filter, the response of which may be controlled by a control signal (212) according to one or more of such factors.
Inventors
- 👤 Kenneth A. Hansen
- 👤 James D. Brake
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:38
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/34; H03G3/344; H04; H04B; H04B1/00; H04B1/06; H04B1/10; H04B1/1027
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
67 words
A noise squelch circuit for a radio receiver, comprising: a demodulator for demodulating a received communication signal having a demodulator output; a filter means for adaptively shaping frequency characteristics of noise present at the demodulator output in response to a control signal, wherein said control signal corresponds to channel spacing of the radio receiver; and squelch means coupled to said filter means for squelching the radio receiver.
Claim 2
Dependent Claim
67 words
A noise squelch circuit for a radio receiver, comprising: a demodulator for demodulating a received communication signal having a demodulator output; a filter means for adaptively shaping frequency characteristics of noise present at the demodulator output in response to a control signal, wherein said control signal corresponds to channel spacing of the radio receiver; and squelch means coupled to said filter means for squelching the radio receiver.
Claim 3
Dependent Claim
67 words
A noise squelch circuit for a radio receiver, comprising: a demodulator for demodulating a received communication signal having a demodulator output; a filter means for adaptively shaping frequency characteristics of noise present at the demodulator output in response to a control signal, wherein said control signal corresponds to deviation of the received communication signal; and squelch means coupled to said filter means for squelching the radio receiver.
Claim 4
Dependent Claim
67 words
A noise squelch circuit for a radio receiver, comprising: a demodulator for demodulating a received communication signal having a demodulator output; a filter means for adaptively shaping frequency characteristics of noise present at the demodulator output in response to a control signal, wherein said control signal corresponds to deviation of the received communication signal; and squelch means coupled to said filter means for squelching the radio receiver.
Claim 5
Dependent Claim
67 words
A radio comprising: means for receiving a received communication signal; a demodulator for demodulating the received communication signal having a demodulator output; a filter means for adaptively shaping frequency characteristics of noise present at the demodulator output in response to a control signal, wherein said control signal corresponds to channel spacing of the radio; and squelch means coupled to said filter means for squelching the radio receiver.
Claim 6
Dependent Claim
67 words
A radio comprising: means for receiving a received communication signal; a demodulator for demodulating the received communication signal having a demodulator output; a filter means for adaptively shaping frequency characteristics of noise present at the demodulator output in response to a control signal, wherein said control signal corresponds to channel spacing of the radio; and squelch means coupled to said filter means for squelching the radio receiver.
Claim 7
Dependent Claim
68 words
A radio comprising: means for receiving a received communication signal; a demodulator for demodulating the received communication signal having a demodulator output; a filter means for adaptively shaping frequency characteristics of noise present at the demodulator output in response to a control signal, wherein said control signal corresponds to deviation of the received communication signal; and squelch means coupled to said filter means for squelching the radio receiver.
Claim 8
Dependent Claim
68 words
A radio comprising: means for receiving a received communication signal; a demodulator for demodulating the received communication signal having a demodulator output; a filter means for adaptively shaping frequency characteristics of noise present at the demodulator output in response to a control signal, wherein said control signal corresponds to deviation of the received communication signal; and squelch means coupled to said filter means for squelching the radio receiver.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-04-11 | 1997-10-11 | 1998-04-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-04-11 | 2001-10-11 | 2002-04-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-04-11 | 2005-10-11 | 2006-04-12 | $7700.00 | Window Closed / Lapsed |