Patent US4748688A successfully refreshed from Google Patents.
US4748688A
Expired / Lapsed
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Electromagnetic wave receiver
Assignee: Emhart Industries Inc
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Filing: 1986-04-28
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Granted: 1988-05-31
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Expires: 2006-04-28
Abstract
Abstract A receiver includes a receiving circuit for receiving an electromagnetic carrier wave modulated by a message signal, a detector ciruit for separating the message signal from the carrier wave, and an output circuit. The detector circuit has a Q ratio sufficiently low that the detectable band width is more than twice the modulation frequency change. The detector output signal has a noise voltage level when no carrier is present that is higher than the voltage of the message signal with a carrier present. An output circuit senses the level of the detector output signal and passes signals with a voltage level below a predetermined level and otherwise blocks the output signal. The filtering of the output circuit is sufficiently low that its response time is faster than a tenth of a second. The output circuit includes a noisy input related to the detector output and a reference input. A pair of diodes connect the noisy input and the reference input enabling the reference input to track the noisy input to prevent false data outputs.
Inventors
- 👤 Ronald J. Coash
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:19
CPC Classifications
H; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/34; H03G3/344; H04; H04B; H04B1/00; H04B1/06; H04B1/16; H04B1/1638
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
99 words
A receiver comprising: means for receiving an electromagnetic carrier wave frequency modulated by a message signal said carrier wave characterized by a modulation frequency change, detector circuit means for separating said message signal from said carrier wave and for producing a detector signal which includes said message signal, said detector circuit means characterized by a detectable bandwidth and having a Q ratio sufficiently low that the detectable bandwidth is more than twice as large as the modulation frequency change; and output means responsive to said detector signal for providing an output signal when said carrier wave is being received.
Claim 2
Dependent Claim
99 words
A receiver comprising: means for receiving an electromagnetic carrier wave frequency modulated by a message signal said carrier wave characterized by a modulation frequency change, detector circuit means for separating said message signal from said carrier wave and for producing a detector signal which includes said message signal, said detector circuit means characterized by a detectable bandwidth and having a Q ratio sufficiently low that the detectable bandwidth is more than twice as large as the modulation frequency change; and output means responsive to said detector signal for providing an output signal when said carrier wave is being received.
Claim 3
Dependent Claim
15 words
The receiver of claim 1 wherein said means for receiving includes an active Butterworth filter.
Claim 4
Dependent Claim
91 words
A receiver comprising: circuit means for receiving an electromagnetic carrier wave modulated by a message signal, detector circuit means for separating said message signal from said carrier wave and for producing a detector signal which includes said message signal, output means responsive to said detector signal for producing an output signal, said output means including a reference voltage input, a noisy input related to said detector signal, and a means for enabling the signal on said reference input to track the signal on said noisy input to prevent false data outputs.
Claim 5
Dependent Claim
91 words
A receiver comprising: circuit means for receiving an electromagnetic carrier wave modulated by a message signal, detector circuit means for separating said message signal from said carrier wave and for producing a detector signal which includes said message signal, output means responsive to said detector signal for producing an output signal, said output means including a reference voltage input, a noisy input related to said detector signal, and a means for enabling the signal on said reference input to track the signal on said noisy input to prevent false data outputs.
Claim 6
Dependent Claim
66 words
A receiver comprising: circuit means for receiving an electromagnetic carrier wave frequency modulated by a message signal; detector circuit means for separating said message signal from said carrier wave and for producing a detector signal which includes said message signal; and output means response to said detector signal for producing an output signal, said output means having a response time of less than approximately 2.5 milliseconds.
Claim 7
Dependent Claim
66 words
A receiver comprising: circuit means for receiving an electromagnetic carrier wave frequency modulated by a message signal; detector circuit means for separating said message signal from said carrier wave and for producing a detector signal which includes said message signal; and output means response to said detector signal for producing an output signal, said output means having a response time of less than approximately 2.5 milliseconds.
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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) | 1991-05-31 | 1991-11-30 | 1992-05-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-31 | 1995-11-30 | 1996-05-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-31 | 1999-11-30 | 2000-05-31 | $7700.00 | Window Closed / Lapsed |