US3783387A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noise detector circuit
Assignee: General Electric Co
•
Filing: 1972-06-14
•
Granted: 1974-01-01
•
Expires: 1992-06-14
Abstract
Abstract In a power-line carrier receiver having a discriminator that produces output signals in response to frequency-shift-keyed signals, a noise detector circuit is provided to squelch the receiver under certain noise conditions. The detector circuit uses two trigger circuits having a signal-to-noise ratio detector threshhold and a noise spike threshhold. If a low signal-to-noise ratio is detected, or if a noise spike is detected, the respective trigger circuit produces a signal to squelch or disable the receiver.
Inventors
- 👤 A Wernli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:18
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/10; H04L27/14
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
231 words
In a power line carrier receiver having a frequency discriminator that produces an output signal in response to a frequency-shift-keyed signal, an improved noise detector circuit comprising: a. input means adapted to be connected to said discriminator for receiving said output signal therefrom; b. a high pass filter connected to said input means; c. a rectifier connected to said high pass filter for producing a rectified signal therefrom; d. a first trigger circuit connected to said rectifier, said first trigger circuit having first reference voltage means against which said rectified signal is compared, said first trigger circuit producing a good condition signal in response to said rectified signal exceeding said first reference voltage and producing a poor condition signal in response to said first reference voltage exceeding said rectified signal; e. a second trigger circuit connected to said rectifier, said second trigger circuit having second reference voltage means against which said rectified signal is compared, said second reference voltage being greater than said first reference voltage, said second trigger circuit producing a good condition signal in response to said second reference voltage exceeding said rectified signal and producing a poor condition signal in response to said rectified signal exceeding said second reference voltage; f. and means connected to said first and second trigger circuits for producing a signal that squelches said receiver in response to either of said poor condition signals.
Claim 2
Dependent Claim
231 words
In a power line carrier receiver having a frequency discriminator that produces an output signal in response to a frequency-shift-keyed signal, an improved noise detector circuit comprising: a. input means adapted to be connected to said discriminator for receiving said output signal therefrom; b. a high pass filter connected to said input means; c. a rectifier connected to said high pass filter for producing a rectified signal therefrom; d. a first trigger circuit connected to said rectifier, said first trigger circuit having first reference voltage means against which said rectified signal is compared, said first trigger circuit producing a good condition signal in response to said rectified signal exceeding said first reference voltage and producing a poor condition signal in response to said first reference voltage exceeding said rectified signal; e. a second trigger circuit connected to said rectifier, said second trigger circuit having second reference voltage means against which said rectified signal is compared, said second reference voltage being greater than said first reference voltage, said second trigger circuit producing a good condition signal in response to said second reference voltage exceeding said rectified signal and producing a poor condition signal in response to said rectified signal exceeding said second reference voltage; f. and means connected to said first and second trigger circuits for producing a signal that squelches said receiver in response to either of said poor condition signals.
Claim 3
Dependent Claim
22 words
The improved noise detector circuit of claim 1 wherein said input means provides for capacitively coupling said input means to said discriminator.
Claim 4
Dependent Claim
19 words
The improved noise detector circuit of claim 1 wherein said high pass filter rejects frequencies substantially below 300 Hertz.
Claim 5
Dependent Claim
25 words
The improved noise detector circuit of claim 1 wherein said second reference voltage is at least three times as great as said first reference voltage.
References Cited (Backward Citations)
US3497812A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-31 | 1977-07-02 | 1978-01-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-31 | 1981-07-02 | 1982-01-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-31 | 1985-07-02 | 1986-01-01 | $7700.00 | Window Closed / Lapsed |