Patent US3790891A successfully refreshed from Google Patents.
US3790891A
Expired / Lapsed
US
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Receiver for a frequency-modulated electro-acoustical signal having squelch means for suppressing noise when no signal is coming through the receiver
Assignee: Individual
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Filing: 1972-08-08
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Granted: 1974-02-05
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Expires: 1992-08-08
Abstract
Abstract The invention relates to a receiver for a frequency-modulated electro-acoustical signal system and more particularly to a compression wave transmission system having a receiver which is adapted to suppress noise signals of frequencies other than the frequencies of the electro-acoustical frequencies, only during periods when no electro-acoustical or compression wave frequency is received. The receiver according to the invention is especially suitable for use in a wireless diver communication system for ultrasonic voice transmission.
Inventors
- 👤 S Bjelvert
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 13:33
CPC Classifications
H; H04; H04B; H04B11/00; H03; H03G; H03G3/00; H03G3/20; H03G3/30; H03G3/34; H03G3/341
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
184 words
An underwater telephone receiver for a frequency-modulated compression wave transmission system having means for suppressing a noise signal having other frequencies than said compression wave, when said compression wave is absent, comprising: a. a transducer for receiving the compression wave and the noise signal and for converting the compression wave to a frequencymodulated electrical intelligence signal and for converting the noise signal into a frequency-modulated electrical noise signal; b. a quadrature detector discriminator for converting said frequency-modulated electrical signals into an amplitudemodulated electrical intelligence signal and into a amplitudemodulated electrical noise signal, respectively; c. said amplitude-modulated intelligence signal having an amplitude level exceeding a predetermined reference amplitude, and said amplitude-modulated noise signal having an amplitude level falling below said reference amplitude; d. means for integrating said amplitude-modulated intelligence signal and noise signal and producing a direct current signal; e. audio amplifying means for amplifying said amplitudemodulated intelligence signal; and f. squelching means for detection of said direct current signal and producing an output which fully saturates said amplifying means when the discriminator generates said amplitude-modulated noise signal in absence of said amplitude-modulated intelligence signal.
Claim 2
Dependent Claim
184 words
An underwater telephone receiver for a frequency-modulated compression wave transmission system having means for suppressing a noise signal having other frequencies than said compression wave, when said compression wave is absent, comprising: a. a transducer for receiving the compression wave and the noise signal and for converting the compression wave to a frequencymodulated electrical intelligence signal and for converting the noise signal into a frequency-modulated electrical noise signal; b. a quadrature detector discriminator for converting said frequency-modulated electrical signals into an amplitudemodulated electrical intelligence signal and into a amplitudemodulated electrical noise signal, respectively; c. said amplitude-modulated intelligence signal having an amplitude level exceeding a predetermined reference amplitude, and said amplitude-modulated noise signal having an amplitude level falling below said reference amplitude; d. means for integrating said amplitude-modulated intelligence signal and noise signal and producing a direct current signal; e. audio amplifying means for amplifying said amplitudemodulated intelligence signal; and f. squelching means for detection of said direct current signal and producing an output which fully saturates said amplifying means when the discriminator generates said amplitude-modulated noise signal in absence of said amplitude-modulated intelligence signal.
Claim 3
Dependent Claim
38 words
A receiver according to claim 1, which includes a rectifying diode, the anode of which is connected to the output of said squelching means, and the cathode of which is connected to an input of said amplifying means.
Claim 4
Dependent Claim
42 words
A receiver according to claim 2, in which a resistor is connected Between a first input terminal of said squelching means and an output terminal of said discriminator, and in which a capacitor is connected between ground and said first input terminal.
References Cited (Backward Citations)
US3218607A
Cited
US3568068A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |