US4087750A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Receiver for detecting and analyzing amplitude or angle modulated waves in the presence of interference
Assignee: United States Department of the Army
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Filing: 1968-05-23
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Granted: 1978-05-02
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Expires: 1988-05-23
Abstract
Abstract This receiver includes in its IF channel a summing network by means of wh the output of a calibrated reference oscillator may be added to the received signals. The frequency and amplitude of the reference oscillator are adjusted to match those of a desired one of several co-channel signals which may be simultaneously present in the IF channel. The combined signals are amplitude limited and applied to a frequency deviation detector in which the wide frequency deviations caused by the interaction of the reference and desired signal are detected. The technique can be used to demodulate angle or amplitude modulated signals obscured by jamming signals and to measure the frequency and amplitude of signals which are similarly obscured.
Inventors
- 👤 Joseph A. Allen
- 👤 William R. Fuschetto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:54
CPC Classifications
H; H04; H04B; H04B1/00; H04B1/06; H04B1/10
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
80 words
A radio receiver comprising, an intermediate frequency channel, a summing network connected to said channel for combining received signals in said intermediate frequency channel and a reference signal, said reference signal being adjustable in frequency and amplitude, and means for selectively angle modulating said reference signal, a wideband amplitude limiter connected to the output of said summing network, and means connected to the output of said limiter to detect frequency deviations outside of the passband of said intermediate frequency channel.
Claim 2
Dependent Claim
80 words
A radio receiver comprising, an intermediate frequency channel, a summing network connected to said channel for combining received signals in said intermediate frequency channel and a reference signal, said reference signal being adjustable in frequency and amplitude, and means for selectively angle modulating said reference signal, a wideband amplitude limiter connected to the output of said summing network, and means connected to the output of said limiter to detect frequency deviations outside of the passband of said intermediate frequency channel.
Claim 3
Dependent Claim
28 words
The circuitry of claim 1 wherein said last-named means comprises a band pass filter tuned outside of the passband of said intermediate frequency channel and an envelope detector.
Claim 4
Dependent Claim
23 words
The circuitry of claim 1 wherein said last-named means comprises frequency modulation detector tuned outside of the passband of said intermediate frequency channel.
Claim 5
Dependent Claim
55 words
The circuitry of claim 1 wherein an audio stage and a filter are connected in parallel to the output of said last-named means, and an oscilloscope, a frequency meter and a digital recorder connected in parallel to the output of said filter, said filter being tuned to block the modulation frequency of said reference oscillator.
Claim 6
Dependent Claim
80 words
A radio receiver comprising, a channel adapted to receive desired incoming signals which may be accompanied by interfering signals, means to superimpose a reference signal on the signals of said channel, means to adjust the amplitude of said reference signal, means to amplitude limit the resulting superimposed signals and to convert the frequency deviations of the limited signal outside of the passband of said channel to a train of direct current pulses, and means to monitor said train of pulses.
Claim 7
Dependent Claim
80 words
A radio receiver comprising, a channel adapted to receive desired incoming signals which may be accompanied by interfering signals, means to superimpose a reference signal on the signals of said channel, means to adjust the amplitude of said reference signal, means to amplitude limit the resulting superimposed signals and to convert the frequency deviations of the limited signal outside of the passband of said channel to a train of direct current pulses, and means to monitor said train of pulses.
Claim 8
Independent Claim
75 words
The method of measuring the amplitude of a received or unknown signal comprising the steps of linearly combining said signal with a reference signal of the same frequency and a calibrated variable amplitude, amplitude limiting said combined signals and detecting the frequency excursions of said limited signals, varying the amplitude of said reference signal until said excursions are maximized whereby the calibrated amplitude of said reference signal equals that of the received or unknown signal.
Claim 9
Independent Claim
75 words
The method of measuring the amplitude of a received or unknown signal comprising the steps of linearly combining said signal with a reference signal of the same frequency and a calibrated variable amplitude, amplitude limiting said combined signals and detecting the frequency excursions of said limited signals, varying the amplitude of said reference signal until said excursions are maximized whereby the calibrated amplitude of said reference signal equals that of the received or unknown signal.
Claim 10
Independent Claim
76 words
The method of measuring the frequency of a received or unknown signal comprising the steps of linearly combining said signal with a reference signal of the same amplitude and with a calibrated variable frequency, amplitude limiting said combined signals and detecting the frequency excursions of said limited signals, varying the frequency of said reference signal until said excursions are maximized, whereby the calibrated frequency of said reference signal equals that of the received or unknown signal.
Claim 11
Independent Claim
76 words
The method of measuring the frequency of a received or unknown signal comprising the steps of linearly combining said signal with a reference signal of the same amplitude and with a calibrated variable frequency, amplitude limiting said combined signals and detecting the frequency excursions of said limited signals, varying the frequency of said reference signal until said excursions are maximized, whereby the calibrated frequency of said reference signal equals that of the received or unknown signal.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-01 | 1981-10-31 | 1982-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-01 | 1985-10-31 | 1986-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-01 | 1989-10-31 | 1990-05-02 | $7700.00 | Window Closed / Lapsed |