US3810067A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical signal filter
Assignee: IOMEC
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Filing: 1973-05-23
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Granted: 1974-05-07
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Expires: 1993-05-23
Abstract
Abstract A filtering technique for removing noise and enhancing the waveform shape of an information signal train. An incoming signal is subjected to a two bit interval delay. The delayed signal is separately summed with and multiplied by the undelayed signal. The resulting sum and product signals are multiplied together and the resulting product signal is summed with the incoming signal delayed by one bit interval. The resulting sum is passed through a low pass filter and used to drive a limit amplifier to produce the filtered output signal.
Inventors
- 👤 R Heidecker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:41
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/06; H04L25/061; H04L25/062; H03; H03K; H03K5/00; H03K5/153
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
106 words
A method of filtering an information signal train having information contained in digit intervals to reduce the data error rate, said method comprising: a. delaying said information signal train by a time interval equivalent to two digit intervals; b. summing the delayed signal train with the received information signal train; c. multiplying the delayed signal train by the received information signal train; d. multiplying the signals resulting from steps (b) and (c); e. delaying the information signal train by a time interval equivalent to one digit interval; and f. summing the signals resulting from step (d) with the information signal train delayed by one digit interval.
Claim 2
Independent Claim
106 words
A method of filtering an information signal train having information contained in digit intervals to reduce the data error rate, said method comprising: a. delaying said information signal train by a time interval equivalent to two digit intervals; b. summing the delayed signal train with the received information signal train; c. multiplying the delayed signal train by the received information signal train; d. multiplying the signals resulting from steps (b) and (c); e. delaying the information signal train by a time interval equivalent to one digit interval; and f. summing the signals resulting from step (d) with the information signal train delayed by one digit interval.
Claim 3
Dependent Claim
22 words
The method of claim 1 further including the step of passing the signals resulting from step (f) through a low pass filter.
Claim 4
Dependent Claim
45 words
The method of claim 1 further including the step of fitering the signals resulting from step (f) with a low pass filter to reject all signals having a frequency higher than about 1.4/t, where t is the duration of the information signal train digit interval.
Claim 5
Dependent Claim
227 words
A signal filter for improving a degraded information signal train containing information in digit intervals, said filter comprising: an input terminal adapted to be coupled to said signal train; a delay element coupled to said input terminal and having a first output for providing a signal train delayed by one digit interval and a second output for providing a signal train delayed by two digit intervals; first summing means coupled to said second output of said delay element and said input terminal for providing a signal representative of the algebraic sum of said information signal train and the signal train delayed by two digit intervals; first multiplier means coupled to said second output of said delay element and said input terminal for providing a signal representative of the signed product of said information signal train and the signal train delayed by two digit intervals; second multiplier means coupled to said first summing means and said first multiplier means for providing a signal representative of the signed product of the output signal from said first summing means and said first multiplier means; and second summing means coupled to said second multiplier means and said first output of said delay element for providing a signal representative of the algebraic sum of said signed product signal from said second multiplier means and said signal train delayed by one digit interval.
Claim 6
Dependent Claim
227 words
A signal filter for improving a degraded information signal train containing information in digit intervals, said filter comprising: an input terminal adapted to be coupled to said signal train; a delay element coupled to said input terminal and having a first output for providing a signal train delayed by one digit interval and a second output for providing a signal train delayed by two digit intervals; first summing means coupled to said second output of said delay element and said input terminal for providing a signal representative of the algebraic sum of said information signal train and the signal train delayed by two digit intervals; first multiplier means coupled to said second output of said delay element and said input terminal for providing a signal representative of the signed product of said information signal train and the signal train delayed by two digit intervals; second multiplier means coupled to said first summing means and said first multiplier means for providing a signal representative of the signed product of the output signal from said first summing means and said first multiplier means; and second summing means coupled to said second multiplier means and said first output of said delay element for providing a signal representative of the algebraic sum of said signed product signal from said second multiplier means and said signal train delayed by one digit interval.
Claim 7
Dependent Claim
18 words
The apparatus of claim 4 wherein said first and second summing means each comprises a linear summing amplifier.
Claim 8
Dependent Claim
15 words
The apparatus of claim 4 wherein said second multiplier means comprises a linear four-quadrant multiplier.
Claim 9
Dependent Claim
18 words
The apparatus of claim 4 wherein said first and second multiplier means each comprises a linear four-quadrant multiplier.
Claim 10
Dependent Claim
20 words
The apparatus of claim 4 further including a low pass filter coupled to the output of said second summing means.
Claim 11
Dependent Claim
26 words
The apparatus of claim 8 wherein said low pass filter has an upper cut-off frequency of 1.4/t, where t is the period of said digit interval.
Claim 12
Dependent Claim
19 words
The apparatus of claim 4 further including a limit amplifier coupled to the output of said second summing means.
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) | 1977-05-06 | 1977-11-05 | 1978-05-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-06 | 1981-11-05 | 1982-05-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-06 | 1985-11-05 | 1986-05-07 | $7700.00 | Window Closed / Lapsed |