US3737783A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Signal-to-noise ratio improving device for receiving systems having two wave collectors
Assignee: Alcatel CIT SA
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Filing: 1971-05-14
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Granted: 1973-06-05
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Expires: 1991-05-14
Abstract
Abstract A signal-to-noise ratio improving device for processing narrow frequency band signals received by two wave collectors (transducers or antennas) and respectively delivered at one and the other of two input terminals in the form of identical useful signals on each of which a different quasi-stationary noise is superposed. The device forms the sum and difference of the noiseaffected signals received at said input terminals and the said difference is processed in a circuit comprising amplitude regulating means, first and second correlators each having two inputs to one of which is fed the said sum and to the other of which are applied, for said first correlator, said amplituderegulated difference and, for said second correlator, the latter said difference delayed by a fixed time interval. The correlators deliver at their respective outputs signals proportional to the time average of the product of the signals applied to their two inputs. The averaged signals are respectively applied to a first input of each one of two multipliers, to a second input of which are respectively applied said amplitude-regulated difference and said delayed amplitude-regulated difference. The outputs of the multipliers deliver new signals which are applied to the inputs of an adder, and the output signal from said adder is applied to an input of a subtractor, to the other input of which said sum of noise-affected signals is applied. The output of the subtractor delivers the improved signal.
Inventors
- 👤 J Oswald
- 👤 Y Rainsard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:13
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/02; H04B7/04; H04B7/08; H04B7/0891; H04B7/0894; G; G01; G01S; G01S13/00; G01S13/87; G01S7/00; G01S7/02; G01S7/42; G06; G06G; G06G7/00; G06G7/12; G06G7/19; G06G7/1928; H04B7/0837; H04B7/0842; H04B7/0848; H04B7/0854
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
170 words
In a receiving system for noise-affected communication signals transmitted in a narrow frequency band centered on a given frequency fo, two wave collectors receiving said signals, amplifying and filtering means processing signals taken from one and the other of said wave collectors and respectively delivering them in the form of two filtered signals to one and the other of two input terminals of a noise reducing circuit, said filtered signals consisting of amplitude-and-phase identical communication signals and noise components superposed thereon; addition and subtraction means fed from said input terminals and delivering the sum and the difference of said filtered signals; amplituderegulating means fed at their input from said signal difference and delivering at their output an amplitude-regulated difference signal having a predetermined constant root-mean-square value; and means for processing said amplitude-regulated signal and for subtractively combining the so processed signal with said sum of filtered signals, whereby there is obtained a new signal, the signal-to-noise power ratio of which is improved relatively to that of said noise-affected communication signals.
Claim 2
Dependent Claim
170 words
In a receiving system for noise-affected communication signals transmitted in a narrow frequency band centered on a given frequency fo, two wave collectors receiving said signals, amplifying and filtering means processing signals taken from one and the other of said wave collectors and respectively delivering them in the form of two filtered signals to one and the other of two input terminals of a noise reducing circuit, said filtered signals consisting of amplitude-and-phase identical communication signals and noise components superposed thereon; addition and subtraction means fed from said input terminals and delivering the sum and the difference of said filtered signals; amplituderegulating means fed at their input from said signal difference and delivering at their output an amplitude-regulated difference signal having a predetermined constant root-mean-square value; and means for processing said amplitude-regulated signal and for subtractively combining the so processed signal with said sum of filtered signals, whereby there is obtained a new signal, the signal-to-noise power ratio of which is improved relatively to that of said noise-affected communication signals.
Claim 3
Dependent Claim
374 words
In a receiving system for nois-affected communication signals transmitted in a narrow frequency band centered on a given frequency fo, two wave collectors receiving said signals, amplifying and filtering means processing signals taken from one and the other of said wave collectors and respectively delivering them in the form of two filtered signals to one and the other of two input terminals of a noise reducing circuit, said filtered signals consisting of amplitude-and-phase identical communication signals and noise components superposed thereon; addition and subtraction means fed from said input terminals and delivering the sum and the difference of said filtered signals; amplitude-regulating means fed at their input from said signal difference and delivering at thEir output an amplitude-regulated difference signal having a predetermined constant root-mean square value, a first correlator means having two inputs respectively fed from said signal sum and amplitued-regulated difference signal and delivering at its output an averaged signal proportional to the time average of the product of said signal sum and amplitued-regulated difference signal; a delay network fed from said amplitude-regulated difference signal and delivering a delayed amplitude-regualted difference signal; a second correlator means having two inputs respectively fed from said signal sum and said delayed amplitude-regulated difference signal and delivering at its output an averaged signal proportional to the time average of the product of said signal sum and said delayed amplitude-regulated difference signal; a first multiplier having an input fed from said amplitude-regulated difference signal and another input fed from the output of said first correlator means and delivering at its output the product of said averaged signal by said amplitude-regulated difference signal; a second multiplier having an input fed from said delayed amplitude regulated difference signal and another input fed said averaged signal from said second correlator means and delivering at its output the product of the latter said difference and averaged signals; an adder circuit having two inputs respectively fed from the outputs of said first and second multipliers, and a subtractor circuit having an input fed from the output of said adder circuit and another input fed said signal sum from said addition means, said adder circuit delivering at its output an improved signal to-noise power ratio relatively to that of said noise-affected communication signals.
Claim 4
Dependent Claim
374 words
In a receiving system for nois-affected communication signals transmitted in a narrow frequency band centered on a given frequency fo, two wave collectors receiving said signals, amplifying and filtering means processing signals taken from one and the other of said wave collectors and respectively delivering them in the form of two filtered signals to one and the other of two input terminals of a noise reducing circuit, said filtered signals consisting of amplitude-and-phase identical communication signals and noise components superposed thereon; addition and subtraction means fed from said input terminals and delivering the sum and the difference of said filtered signals; amplitude-regulating means fed at their input from said signal difference and delivering at thEir output an amplitude-regulated difference signal having a predetermined constant root-mean square value, a first correlator means having two inputs respectively fed from said signal sum and amplitued-regulated difference signal and delivering at its output an averaged signal proportional to the time average of the product of said signal sum and amplitued-regulated difference signal; a delay network fed from said amplitude-regulated difference signal and delivering a delayed amplitude-regualted difference signal; a second correlator means having two inputs respectively fed from said signal sum and said delayed amplitude-regulated difference signal and delivering at its output an averaged signal proportional to the time average of the product of said signal sum and said delayed amplitude-regulated difference signal; a first multiplier having an input fed from said amplitude-regulated difference signal and another input fed from the output of said first correlator means and delivering at its output the product of said averaged signal by said amplitude-regulated difference signal; a second multiplier having an input fed from said delayed amplitude regulated difference signal and another input fed said averaged signal from said second correlator means and delivering at its output the product of the latter said difference and averaged signals; an adder circuit having two inputs respectively fed from the outputs of said first and second multipliers, and a subtractor circuit having an input fed from the output of said adder circuit and another input fed said signal sum from said addition means, said adder circuit delivering at its output an improved signal to-noise power ratio relatively to that of said noise-affected communication signals.
Claim 5
Dependent Claim
30 words
In a receiving system as claimed in claim 2, the arrangement in which said filtering means consist of a narrow-pass band filter having its pass band centered on frequency fo.
Claim 6
Dependent Claim
33 words
In a receiving system as claimed in claim 2, the arrangement in which said amplitude-regulating means consist of an amplifier provided with a gain control circuit fed from the output of said amplifier.
Claim 7
Dependent Claim
27 words
In a receiving system as claimed in claim 2, the arrangement in which said amplitude-regulating means consist of a limiter followed by a narrow-band band pass filter.
Claim 8
Dependent Claim
269 words
In a receiving system for noise-affected communication signals transmitted in a narrow frequency band centered on a given frequency fo, two wave collectors receiving said signals, amplifying and filtering means processing signals taken from one and the other of said wave collectors and respectively delivering them in the form of two filtered signals to one and the other of two input terminals of a noise reducing circuit, said filtered signals consisting of amplitude-and-phase identical communication signals and noise components superposed thereon; addition and subtraction means fed from said input terminals and delivering the sum and the difference of said filtered signals; amplitude-regulating means fed at their input from said signal difference and delivering at their output an amplitued-regulated difference signal having a predetermined constant root-mean-square value; a delay network fed from said amplitude-regulated difference signal and delivering a delayed amplitude-regulated difference signal; correlator means having two inputs respectively fed from said signal sum and said delayed amplitude-regulated difference signal and delivering at its output an averaged signal proportional to the time average of the product of said signal sum and said delayed amplitude-regulated difference signal; a multiplier having an input fed from said delayed amplitude-regulated difference signal and another input fed from said averaged signal and delivering at its output the product of the latter said difference and averaged signals; and a subtractor circuit having an input fed from the output of said multiplier and another input fed said signal sum from said addition means, said subtracTor circuit delivering at its output an improved signal having an improved signal-to-noise power ratio relatively to that of said noise-affected communication signals.
Claim 9
Dependent Claim
269 words
In a receiving system for noise-affected communication signals transmitted in a narrow frequency band centered on a given frequency fo, two wave collectors receiving said signals, amplifying and filtering means processing signals taken from one and the other of said wave collectors and respectively delivering them in the form of two filtered signals to one and the other of two input terminals of a noise reducing circuit, said filtered signals consisting of amplitude-and-phase identical communication signals and noise components superposed thereon; addition and subtraction means fed from said input terminals and delivering the sum and the difference of said filtered signals; amplitude-regulating means fed at their input from said signal difference and delivering at their output an amplitued-regulated difference signal having a predetermined constant root-mean-square value; a delay network fed from said amplitude-regulated difference signal and delivering a delayed amplitude-regulated difference signal; correlator means having two inputs respectively fed from said signal sum and said delayed amplitude-regulated difference signal and delivering at its output an averaged signal proportional to the time average of the product of said signal sum and said delayed amplitude-regulated difference signal; a multiplier having an input fed from said delayed amplitude-regulated difference signal and another input fed from said averaged signal and delivering at its output the product of the latter said difference and averaged signals; and a subtractor circuit having an input fed from the output of said multiplier and another input fed said signal sum from said addition means, said subtracTor circuit delivering at its output an improved signal having an improved signal-to-noise power ratio relatively to that of said noise-affected communication signals.
Claim 10
Dependent Claim
30 words
In a receiving system as claimed in claim 6, the arrangement in which said filtering means consists of a narrow-pass band filter having its pass band centered on frequency fo.
Claim 11
Dependent Claim
33 words
In a receiving system as claimed in claim 6, the arrangement in which said amplitude-regulating means consists of an amplifier provided with a gain control circuit fed from the output of said amplifier.
Claim 12
Dependent Claim
27 words
In a receiving system as claimed in claim 6, the arrangement in which said amplitude-regulating means consist of a limiter followed by a narrow-band band pass filter.
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) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |