US3944932A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Receiver filtering out both systematic pulse noise and random noise
Assignee: General Electric Co
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Filing: 1974-12-05
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Granted: 1976-03-16
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Expires: 1994-12-05
Abstract
Abstract A continuous wave (c.w.) receiver is described comprising an amplitude limiting section, a commutating filter section, peak detecting means, and a threshold device. The receiver detects the presence or absence of an incoming signal over a very narrow, adjustable bandwidth. The limiting section clips the signal and noise at a predetermined amplitude and, in combination with the commutating filter, reduces the effect of noise, particularly impulse noise. The peak detector selects the highest output from the commutating filter and, in combination with the commutating filter, performs a pseudo-synchronization function when the received signal and an internal signal are not synchronized exactly.
Inventors
- 👤 Kouan Fong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:54
CPC Classifications
H; H03; H03G; H03G11/00; H03D; H03D1/00; H03D1/02; H03D1/04; H04; H04B; H04B1/00; H04B1/06; H04B1/10
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
115 words
A receiver for receiving and detecting tone signals in a noisy environment, where the amplitude of impulse noise exceeds the amplitude of the received signal, comprising: an amplitude limiting section for excluding noise above a predetermined amplitude; a commutating filter section coupled to said amplitude limiting section, for generating a plurality of voltages indicative of a received signal within the passband of the filter section; peak detection means, coupled to said commutating filter, for selecting the one of said voltages having the largest amplitude; and threshold detecting means, coupled to said peak detecting means, for producing an output signal when said selected voltage exceeds a predetermined threshold to indicate the presence of a received tone.
Claim 2
Dependent Claim
115 words
A receiver for receiving and detecting tone signals in a noisy environment, where the amplitude of impulse noise exceeds the amplitude of the received signal, comprising: an amplitude limiting section for excluding noise above a predetermined amplitude; a commutating filter section coupled to said amplitude limiting section, for generating a plurality of voltages indicative of a received signal within the passband of the filter section; peak detection means, coupled to said commutating filter, for selecting the one of said voltages having the largest amplitude; and threshold detecting means, coupled to said peak detecting means, for producing an output signal when said selected voltage exceeds a predetermined threshold to indicate the presence of a received tone.
Claim 3
Dependent Claim
22 words
The receiver as set forth in claim 1 wherein said commutating filter section comprises at least two commutating filters connected in cascade.
Claim 4
Dependent Claim
20 words
The receiver as set forth in claim 2 wherein said commutating filters have the same center frequencies and different bandwidths.
Claim 5
Dependent Claim
36 words
The receiver as set forth in claim 3 wherein the bandwidth of the commutating filter coupled to said amplitude limiting section is wider than the bandwidth of the commutating filter coupled to said peak detecting means.
Claim 6
Dependent Claim
20 words
The receiver as set forth in claim 4 wherein said bandwidths are in the ratio of approximately three to one.
Claim 7
Dependent Claim
19 words
The receiver as set forth in claim 1 wherein said peak detecting means comprises a voltage doubling peak detector.
Claim 8
Dependent Claim
25 words
The receiver as set forth in claim 1 wherein said amplitude limiting section comprises an automatic gain controlled amplifier and an amplitude limiter coupled thereto.
Claim 9
Dependent Claim
49 words
The receiver as set forth in claim 1 wherein said amplitude limiting section comprises: a wide-band filter having a different center frequency that said commutating filter section; a pre-amplifier and follower stage coupled to said wide-band filter; and at least two cascaded limiting amplifiers coupled to said follower stage.
Claim 10
Dependent Claim
63 words
The receiver as set forth in claim 1 wherein said amplitude limiting section comprises: a wide-band filter having a different center frequency than said commutating filter section; a pre-amplifier and follower stage coupled to said wide-band filter; at least two cascaded limiting amplifiers coupled to said follower stage; and wherein said commutating filter means comprises at least two commutating filters connected in cascade.
Claim 11
Dependent Claim
20 words
The receiver as set forth in claim 9 wherein said commutating filters have the same center frequencies and different bandwidths.
Claim 12
Dependent Claim
36 words
The receiver as set forth in claim 10 wherein the bandwidth of the commutating filter coupled to said amplitude limiting section is wider than the bandwidth of the commutating filter coupled to said peak detecting means.
Claim 13
Dependent Claim
20 words
The receiver as set forth in claim 11 wherein said bandwidths are in the ratio of approximately three to one.
Claim 14
Dependent Claim
19 words
The receiver as set forth in claim 12 wherein said peak detecting means comprises a voltage doubling peak detector.
Claim 15
Dependent Claim
40 words
The receiver as set forth in claim 9 wherein the frequency displacement between the center frequencies of said wide-band filter and said commutating filter causes a phase shift of at least 4π radians over the duration of the received signal.
Claim 16
Dependent Claim
47 words
The receiver as set forth in claim 1 and further comprising means interconnecting the output of said commutating filter means and the input of said peak detecting means for reducing amplitude variations in the output of said peak detector due to phase variations of the 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) | 1979-03-16 | 1979-09-15 | 1980-03-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-03-16 | 1983-09-15 | 1984-03-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-03-16 | 1987-09-15 | 1988-03-16 | $7700.00 | Window Closed / Lapsed |