US3829779A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multilevel code transmission system
Assignee: NEC Corp
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Filing: 1973-02-01
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Granted: 1974-08-13
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Expires: 1993-02-01
Abstract
Abstract A multilevel code transmission system is made capable of transmission and reception of correct signals even if the demodulation carrier is 180 degrees out of phase by dividing the levels of a multilevel code to be transmitted into pairs and subjecting the transmission signal to differential coding, pair by pair. At the receiver, the levels are again divided into pairs, and the differentially coded signal is inversely converted.
Inventors
- 👤 H Fujimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:11
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/38; H04L25/40; H04L25/49; H04L25/497; H04L27/00; H04L27/02; H04L27/06; H04L27/066
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
360 words
A multilevel code transmission system for transmission of a data signal in the form of an N-level, where N is an integer greater than two, code signal based on a partial response coding, comprising: a transmitter including means for providing said data signal in the form of parallel binary codes: means for monitoring each pair of input parallel binary codes representing N-i and i levels, where i represents all positive integers smaller than N, of said N-level code signal; means for delivering an output parallel binary code i level when the level monitored by said monitoring means is N - i or i and is equal to the N - i or i level last monitored by said monitoring means, and for delivering another output parallel binary code representing N - i level when the level monitored by said monitoring means is N - i or i and is different from the N - i or i level last monitored by said monitoring means, means for converting a part of said input parallel binary codes and the outputs of said delivering means to said N-level code signal based on the partial response coding, and means for amplitude-modulating said N-level code signal thereby to transmit the modulated signal together with a pilot carrier signal to a receiver; and a receiver including means for applying a coherent demodulation to said transmitted modulated signal thereby to regenerate said input parallel binary codes, means for monitoring each pair of said regenerated input parallel binary codes; and means for delivering a regenerated output parallel binary code representing i level when the level monitored by the last mentioned monitoring means is N - i or i and is equal to the N - i or i level last monitored by the last mentioned monitoring means, and for delivering another regenerated parallel binary code representing N - i level when the level monitored by the last mentioned monitoring means is N - i or i and is different from the N - i or i level last monitored by said last mentioned monitoring means, thereby to regenerate said data signal in the form of parallel binary codes.
Claim 2
Dependent Claim
360 words
A multilevel code transmission system for transmission of a data signal in the form of an N-level, where N is an integer greater than two, code signal based on a partial response coding, comprising: a transmitter including means for providing said data signal in the form of parallel binary codes: means for monitoring each pair of input parallel binary codes representing N-i and i levels, where i represents all positive integers smaller than N, of said N-level code signal; means for delivering an output parallel binary code i level when the level monitored by said monitoring means is N - i or i and is equal to the N - i or i level last monitored by said monitoring means, and for delivering another output parallel binary code representing N - i level when the level monitored by said monitoring means is N - i or i and is different from the N - i or i level last monitored by said monitoring means, means for converting a part of said input parallel binary codes and the outputs of said delivering means to said N-level code signal based on the partial response coding, and means for amplitude-modulating said N-level code signal thereby to transmit the modulated signal together with a pilot carrier signal to a receiver; and a receiver including means for applying a coherent demodulation to said transmitted modulated signal thereby to regenerate said input parallel binary codes, means for monitoring each pair of said regenerated input parallel binary codes; and means for delivering a regenerated output parallel binary code representing i level when the level monitored by the last mentioned monitoring means is N - i or i and is equal to the N - i or i level last monitored by the last mentioned monitoring means, and for delivering another regenerated parallel binary code representing N - i level when the level monitored by the last mentioned monitoring means is N - i or i and is different from the N - i or i level last monitored by said last mentioned monitoring means, thereby to regenerate said data signal in the form of parallel binary codes.
Claim 3
Dependent Claim
118 words
A multilevel code transmission system as recited in claim 1 wherein said means for monitoring in said transmitter includes: code detecting means for providing N - i and i designating codes corresponding to the N - i level and the i-level of said N-level code signal, and said means for delivering in said transmitter includes: memory means for storing an indication of the preceding delivered i designating or N - i designating code, and comparing means responsive to the outputs of said code detecting means and said memory means for generating said i designating code when there is coincidence between said inputs and for generating said N - i designating code where there is non-coincidence between said inputs.
Claim 4
Dependent Claim
51 words
A multilevel code transmission system as recited in claim 2 wherein said memory means includes bistable means responsive to said code detecting means for inverting the preceding N - i designating code or the i designating code when said detecting means provides an output corresponding to the N - i level.
Claim 5
Dependent Claim
120 words
A multilevel code transmission system as recited in claim 1 wherein said means for monitoring in said receiver includes: code detecting means for providing N - i and i designating codes corresponding to the N - i level and the i level of said N-level code signal, and said means for delivering in said receiver includes: memory means for storing an indication of the preceding delivered i designating or N - i designating code, and comparing means responsive to the outputs of said code detecting means and the said memory means for generating said i designating code when there is coincidence between said inputs and for generating said N - i designating code when there is non-coincidence between said inputs.
Claim 6
Dependent Claim
238 words
A multilevel code transmission system as recited in claim 1 wherein said means for monitoring in said transmitter includes: first code detecting means for providing N - i and i designating codes corresponding to the N - i level and the i level of said N-level code signal; and said means for delivering in said transmitter includes: first memory means for storing an indication of the preceding delivered i designating or N - i designating code, and first comparing means responsive to the outputs of said first detecting means and said first memory means for generating said i designating code when there is coincidence between said inputs and for generating said N - i designating code when there is non-coincidence between said inputs, and wherein said means for monitoring in said receiver includes: second code detecting means for providing N - i and i designating codes corresponding to the N - i level and the i level of said N-level code signal, and said means for delivering in said receiver includes: second memory means for storing an indication of the preceding delivered i designating or N - i designating code, and second comparing means responsive to the outputs of said second code detecting means and said second memory means for generating said i designating code when there is coincidence between said inputs and for generating saId N - i designating code when there is non-coincidence between said inputs.
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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) | 1977-08-12 | 1978-02-11 | 1978-08-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-08-12 | 1982-02-11 | 1982-08-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-08-12 | 1986-02-11 | 1986-08-13 | $7700.00 | Window Closed / Lapsed |