US3622983A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pseudodensity modulation system
Assignee: Nortel Networks Ltd
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Filing: 1969-10-10
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Granted: 1971-11-23
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Expires: 1989-10-10
Abstract
Abstract Data at a first bit rate which is to be transmitted on a data line having a much higher bit rate is encoded in a (3, 1) block code which is repeated as many times as necessary to fill all available bits on the data link. This data may be detected at the receiving end of the data link by the use of a low-pass filter, and the data can be reconstituted with very simple equipment.
Inventors
- 👤 Jacques V Deregnaucourt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:09
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/4902; H04L25/4906; H04L7/00; H04L7/02; H04L7/027
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
217 words
Apparatus for transmitting binary data of a given bit rate on a transmission link having a higher operating bit rate comprising a free-running clock generating output pulses at said higher bit rate of said transmission link, a counter-of-three connected to said free-running clock, and adapted to provide three outputs in time sequence, the first and third outputs of said counter-ofthree being combined by a first OR circuit to provide a block code of the form 101, the second output from said counter-ofthree being of the form 010, a Schmidt trigger connected to the source of binary data and having two outputs, one of said outputs being energized by the ZERO state of said binary data and the other of said outputs being energized by the ONE state of said binary data, said 0 output of said Schmidt trigger and said second output of said counter-of-three being fed to the inputs of a first AND circuit, the 1 output of said Schmidt trigger and the output of said first OR circuit being fed to the inputs of a second AND circuit, the outputs of said two AND circuits being fed to a second OR circuit whereby the output from said second OR circuit is a binary (3, 1) block code at the bit rate of the data link.
Claim 2
Dependent Claim
217 words
Apparatus for transmitting binary data of a given bit rate on a transmission link having a higher operating bit rate comprising a free-running clock generating output pulses at said higher bit rate of said transmission link, a counter-of-three connected to said free-running clock, and adapted to provide three outputs in time sequence, the first and third outputs of said counter-ofthree being combined by a first OR circuit to provide a block code of the form 101, the second output from said counter-ofthree being of the form 010, a Schmidt trigger connected to the source of binary data and having two outputs, one of said outputs being energized by the ZERO state of said binary data and the other of said outputs being energized by the ONE state of said binary data, said 0 output of said Schmidt trigger and said second output of said counter-of-three being fed to the inputs of a first AND circuit, the 1 output of said Schmidt trigger and the output of said first OR circuit being fed to the inputs of a second AND circuit, the outputs of said two AND circuits being fed to a second OR circuit whereby the output from said second OR circuit is a binary (3, 1) block code at the bit rate of the data link.
Claim 3
Dependent Claim
124 words
Apparatus for receiving binary data transmitted in a (3, 1) block code at a bit rate at least three times higher than the rate of said binary data comprising a low-pass filter tuned to reject all frequencies above the third subharmonic of said bit rate of the (3, 1) block code, a Schmidt trigger connected to the output of said low-pass filter, the output of said Schmidt trigger being fed to a binary data output circuit, and to a tuned circuit resonant at the frequency of said binary data, the output of said tuned circuit being coupled to a squaring circuit, the output of said squaring circuit being coupled to said output circuit whereby said binary data is reconstituted for transmission to user equipment.
Claim 4
Dependent Claim
124 words
Apparatus for receiving binary data transmitted in a (3, 1) block code at a bit rate at least three times higher than the rate of said binary data comprising a low-pass filter tuned to reject all frequencies above the third subharmonic of said bit rate of the (3, 1) block code, a Schmidt trigger connected to the output of said low-pass filter, the output of said Schmidt trigger being fed to a binary data output circuit, and to a tuned circuit resonant at the frequency of said binary data, the output of said tuned circuit being coupled to a squaring circuit, the output of said squaring circuit being coupled to said output circuit whereby said binary data is reconstituted for transmission to user equipment.
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) | 1974-11-22 | 1975-05-24 | 1975-11-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-22 | 1979-05-24 | 1979-11-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-22 | 1983-05-24 | 1983-11-23 | $7700.00 | Window Closed / Lapsed |