US3659202A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Data transmission system
Assignee: NEC Corp
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Filing: 1970-05-21
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Granted: 1972-04-25
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Expires: 1990-05-21
Abstract
Abstract A data transmission system of the type for transmitting multilevel information signals in the form of discretely shifted phases of a carrier wave includes a phase shifter in the transmitter responsive to a level change in the multi-level information signal for unidirectionally phase shifting the carrier. The phase shifter includes an oscillator generating a signal of mfc where fc is the carrier frequency and m is the number of phases. At the receiver, a phase detector derives the input carrier phase as a voltage level which is amplitude discriminated and the multi-level signal is logically derived.
Inventors
- 👤 Hisashi Kaneko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 19:13
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/18; H04L27/22; H04L27/233; H04L27/2332; H04L27/20; H04L27/2032; H04L27/2053; H04L27/2057
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
133 words
In a data transmission system of the type for transmitting a non-predetermined sequence of information signals at first and second levels in the form of discretely shifted phases of a carrier wave and for deriving the information signals therefrom at the receiving end, and including a transmitter and receiver, the improvement comprising: means in the transmitter for generating a carrier wave; means for unidirectionally phase shifting said carrier wave by continuously advancing the phase of said carrier in one direction by a value 360/m *, where m is an integer greater than 2, said value not exceeding 120*, every time said information signal changes from one of said levels to the other of said levels throughout the sequence; and means in the receiver for unambiguously deriving said information signal from said phase changes.
Claim 2
Dependent Claim
133 words
In a data transmission system of the type for transmitting a non-predetermined sequence of information signals at first and second levels in the form of discretely shifted phases of a carrier wave and for deriving the information signals therefrom at the receiving end, and including a transmitter and receiver, the improvement comprising: means in the transmitter for generating a carrier wave; means for unidirectionally phase shifting said carrier wave by continuously advancing the phase of said carrier in one direction by a value 360/m *, where m is an integer greater than 2, said value not exceeding 120*, every time said information signal changes from one of said levels to the other of said levels throughout the sequence; and means in the receiver for unambiguously deriving said information signal from said phase changes.
Claim 3
Dependent Claim
75 words
The improvement claimed in claim 1, in which said phase shifting means comprises an oscillator generAting a signal of a frequency mfc where fc is the carrier frequency, an m-phase signal generator coupled to said oscillator, a phase shift modulator coupled to said m-phase generator, and a control circuit responsive to said multi-valued signal and coupled to said phase shift modulator for unidirectionally phase shifting said carrier wave every time said information signal changes levels.
Claim 4
Dependent Claim
41 words
The improvement claimed in claim 2, wherein said means in said receiver comprises a phase shift detector for deriving the input carrier phase as a voltage level, and an amplitude discriminator coupled to said phase detector for deriving said information signal.
Claim 5
Dependent Claim
34 words
The improvement claimed in claim 3, wherein said amplitude discriminator comprises a multi-output comparator for comparing the voltage level with preset reference voltages, and a logic circuit coupled to the multi-outputs of said comparator.
References Cited (Backward Citations)
US3335369A
Cited
US3421088A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-25 | 1975-10-25 | 1976-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-25 | 1979-10-25 | 1980-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-25 | 1983-10-25 | 1984-04-25 | $7700.00 | Window Closed / Lapsed |