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US3849595A
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Facsimile signal transmission system
Assignee: NEC Corp
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Filing: 1973-09-27
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Granted: 1974-11-19
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Expires: 1993-09-27
Abstract
Abstract A facsimile transmission system is disclosed which uses both amplitude and phase modulation. The amplitude and phase of the transmitted signal are selected in correspondence with the binary values of an input facsimile signal. This is accomplished by first converting the input binary facsimile signal to a binary code indicating state numbers periodically assigned to the two alternate levels of the input facsimile signal. This binary code is then used to develop two other binary codes which in turn are used to generate two kinds of amplitude-indicating signals. These amplitude-indicating signals are quadrature-amplitude-modulated for transmission. At the receiving end, the signal is quadratureamplitude-demodulated to generate the two kinds of amplitudeindicating signals which are converted to two binary codes. These binary codes are decoded to produce the original facsimile signal.
Inventors
- 👤 T Ishiguro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 19:11
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/41; H04N1/411; H04N1/413; H04N1/4135; H04L; H04L27/00; H04L27/32; H04L27/34; H04L27/38; H04L27/3818; H04L27/3836
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
255 words
A facsimile signal transmission system comprising: a transmitting apparatus including: means for converting an input binary facsimile signal to a first binary code signal indicating state numbers succeedingly and periodically assigned to the alternatively generated two levels of said input binary facsimile signal; odd state numbers being assigned to one of the levels of said facsimile signal and even state numbers to another of the levels of said facsimile signal; means for generating from said firSt binary code signal a second binary code signal changing from one to another codes every time said state numbers change from an odd number to an even number; means for generating from said first binary code signal a third binary code signal changing from one to another codes every time said state numbers change from an even number to an odd number; means responsive to said second and third binary code signals for generating two kinds of amplitude-indicating signals, each indicating at least three kinds of amplitudes; and means for quadrature-amplitude-modulating quadrature carriers with said two kinds of amplitude-indicating signals thereby to transmit the quadrature-amplitude-modulated signal via a transmission line to a receiving apparatus; and said receiving apparatus including: means for quadrature-amplitude-demodulating the received quadrature-amplitude-modulated signal thereby to generate two kinds of amplitude-indicating signals; means for converting the last-mentioned two kinds of amplitudeindicating signals to two kinds of binary code signals corresponding to said second and third binary code signals; and means responsive to the last-mentioned two kinds of binary code signals for regenerating said input binary facsimile signal.
Claim 2
Dependent Claim
255 words
A facsimile signal transmission system comprising: a transmitting apparatus including: means for converting an input binary facsimile signal to a first binary code signal indicating state numbers succeedingly and periodically assigned to the alternatively generated two levels of said input binary facsimile signal; odd state numbers being assigned to one of the levels of said facsimile signal and even state numbers to another of the levels of said facsimile signal; means for generating from said firSt binary code signal a second binary code signal changing from one to another codes every time said state numbers change from an odd number to an even number; means for generating from said first binary code signal a third binary code signal changing from one to another codes every time said state numbers change from an even number to an odd number; means responsive to said second and third binary code signals for generating two kinds of amplitude-indicating signals, each indicating at least three kinds of amplitudes; and means for quadrature-amplitude-modulating quadrature carriers with said two kinds of amplitude-indicating signals thereby to transmit the quadrature-amplitude-modulated signal via a transmission line to a receiving apparatus; and said receiving apparatus including: means for quadrature-amplitude-demodulating the received quadrature-amplitude-modulated signal thereby to generate two kinds of amplitude-indicating signals; means for converting the last-mentioned two kinds of amplitudeindicating signals to two kinds of binary code signals corresponding to said second and third binary code signals; and means responsive to the last-mentioned two kinds of binary code signals for regenerating said input binary facsimile signal.
Claim 3
Dependent Claim
45 words
A facsimile signal transmission system as recited in claim 1 wherein said means in said transmitting apparatus for converting an input binary facsimile signal comprises binary counting means for receiving said binary facsimile signal and providing said first binary code signal as a parallel output.
Claim 4
Dependent Claim
33 words
A facsimile signal transmission system as recited in claim 2 wherein said two means in said transmitting apparatus responsive to said second and third binary code signals are first and second digital-to-analog convertors.
Claim 5
Dependent Claim
37 words
A facsimile signal transmission system as recited in claim 3 wherein said means in said receiving apparatus for converting two kinds of amplitude-indicating signals to two kinds of binary code signals are first and second digital-to-analog convertors.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-18 | 1978-05-20 | 1978-11-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-18 | 1982-05-20 | 1982-11-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-18 | 1986-05-20 | 1986-11-19 | $7700.00 | Window Closed / Lapsed |