Patent US4567601A successfully refreshed from Google Patents.
US4567601A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Three-to-two level digital signal conversions and vice versa
Assignee: British Telecommunications PLC
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Filing: 1983-07-18
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Granted: 1986-01-28
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Expires: 2003-07-18
Abstract
Abstract A three level signal is converted to a two level signal for transmission through a bi-level digital device by separating the opposite polarity parts of the three level signal. One part is inverted at an inverter and devices such as monostables are used to form two pulse trains in which the pulse lengths are different. The pulse trains are combined at a mixer and then transmitted through the device. Also disclosed is a decoder for decoding the pulses after transmission through the device.
Inventors
- 👤 Peter J. Mountain
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 22:21
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/4902; H04L25/4917; H04L25/4923; H04L25/4925
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
81 words
A method of converting a three level signal for transmission through a bi-level digital device comprising separating the opposite polarity parts of the three level signal and inverting one part, converting one said part to pulses having a first pulse length and converting the other said part to pulses having a second pulse length which is different from said first pulse length, combining and transmitting said pulses through the digital device and decoding said pulses to regenerate the three level signal.
Claim 2
Independent Claim
81 words
A method of converting a three level signal for transmission through a bi-level digital device comprising separating the opposite polarity parts of the three level signal and inverting one part, converting one said part to pulses having a first pulse length and converting the other said part to pulses having a second pulse length which is different from said first pulse length, combining and transmitting said pulses through the digital device and decoding said pulses to regenerate the three level signal.
Claim 3
Dependent Claim
39 words
A method as claimed in claim 1 wherein the first pulse length is one half the pulse length of the three level signal and the second pulse length is 1.5. times the pulse length of the three level signal.
Claim 4
Dependent Claim
86 words
A method as claimed in claim 1 wherein the decoding step comprises forming a waveform comprising a series of pulses, one for each pulse transmitted through said device, each said pulse having a length corresponding to the pulse length of the three level signal, forming an inverted version of the transmitted pulses, sampling and gating the transmitted pulses and the inverted pulses with said waveform to produce two pulse trains, inverting one said pulse train and mixing the pulse trains to produce the three level signal.
Claim 5
Dependent Claim
94 words
A converter for converting a three level signal having pulses of first and second opposite polarity levels and of a third intermediate level to a bi-level pulse signal, said converter comprising: means for separating the opposite polarity levels of the signal and inverting said first level, means for converting occurrence of said first level to pulses having a first pulse length and for converting occurrences of said second level to pulses having a second pulse length which is different from said first pulse length; and means for combining said first and second length pulses.
Claim 6
Dependent Claim
94 words
A converter for converting a three level signal having pulses of first and second opposite polarity levels and of a third intermediate level to a bi-level pulse signal, said converter comprising: means for separating the opposite polarity levels of the signal and inverting said first level, means for converting occurrence of said first level to pulses having a first pulse length and for converting occurrences of said second level to pulses having a second pulse length which is different from said first pulse length; and means for combining said first and second length pulses.
Claim 7
Dependent Claim
39 words
A converter as claimed in claim 4 wherein the first pulse length is one half the pulse length of the three level signal and the second pulse length is 1.5 times the pulse length of the three level signal.
Claim 8
Dependent Claim
117 words
A converter as claimed in claim 4 including means for decoding the said combined pulses, said decoding means comprising: means for forming a waveform comprising a series of pulses, one for each pulse transmitted through said device, each said pulse having a pulse length corresponding to the pulse length of the three level signal, means for forming an inverted version of the combined pulses, means for sampling and gating the combined pulses and inverted pulses with said waveform to produce two pulse trains, means for inverting one of said two pulse trains, and means for combining said inverted pulse train with the remaining other one of said two pulse trains, to produce a decoded three level signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-01-27 | 1989-07-29 | 1990-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-27 | 1993-07-29 | 1994-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-27 | 1997-07-29 | 1998-01-28 | $7700.00 | Window Closed / Lapsed |