Patent US3673322A successfully refreshed from Google Patents.
US3673322A
Expired / Lapsed
US
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Facsimile transmission system
Assignee: SHINTRON CO Inc
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Filing: 1970-05-28
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Granted: 1972-06-27
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Expires: 1990-05-28
Abstract
Abstract A facsimile transmission system employs a rotating drum at the transmitter upon which the original document is mounted and a synchronously rotating drum at the receiver having marking means for producing the facsimile. ''''Video'''' signals obtained by scanning the original document with a photosensitive device are made to modulate a carrier to convey black and white information by the relative proportions of 0* and 180* phases in the modulated carrier while the shade of black or white is conveyed by the amplitude of the modulated carrier. At the receiver, the modulated carrier is synchronously demodulated to recreate the video signals which are then used to control the marking means so as to produce a facsimile of the original document.
Inventors
- 👤 Larry K Baxter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:13
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/00095; H04N1/32; H04N1/36
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
176 words
A facsimile transmission system having a facsimile transmitter for providing black and white information from an original document, the facsimile transmitter comprising, an electro-optical device for scanning the original document; means coupled to the electro-optical device for deriving a modulating signal representing the information on the original document, said means causing the modulating signal to be a signal having a shifted reference level representing a shade of gray and causing the peak amplitude on one side of the reference level to represent maximum white and the peak amplitude on the other side of the reference level to represent maximum black; a source providing a carrier signal; and modulator means having the carrier signal and the modulating signal applied to its inputs, the modulator means providing an amplitude modulated output signal whose carrier is shifted in phase whenever the modulating signal crosses said shifted reference level whereby the output of the modulator means is a signal whose carrier phase conveys information of blackness or whiteness and whose amplitude conveys information of the shade of black or white.
Claim 2
Dependent Claim
176 words
A facsimile transmission system having a facsimile transmitter for providing black and white information from an original document, the facsimile transmitter comprising, an electro-optical device for scanning the original document; means coupled to the electro-optical device for deriving a modulating signal representing the information on the original document, said means causing the modulating signal to be a signal having a shifted reference level representing a shade of gray and causing the peak amplitude on one side of the reference level to represent maximum white and the peak amplitude on the other side of the reference level to represent maximum black; a source providing a carrier signal; and modulator means having the carrier signal and the modulating signal applied to its inputs, the modulator means providing an amplitude modulated output signal whose carrier is shifted in phase whenever the modulating signal crosses said shifted reference level whereby the output of the modulator means is a signal whose carrier phase conveys information of blackness or whiteness and whose amplitude conveys information of the shade of black or white.
Claim 3
Dependent Claim
33 words
The facsimile transmission system according to claim 1, wherein the transmitter further comprises means for recurrently causing the signal output of the modulator means to simultaneously have a predetermined phase and peak amplitude.
Claim 4
Dependent Claim
32 words
The facsimile transmission system according to claim 2, wherein the modulator means comprises a balanced modulator which provides an amplitude modulated suppressed carrier output signal whose suppressed carrier exhibits 180* phase shifts.
Claim 5
Dependent Claim
37 words
The facsimile transmission system according to claim 3, wherein the transmitter further comprises transducer means coupled to the output of the balanced modulator for changing the electrical output signal to an acoustic signal conveying the same information.
Claim 6
Dependent Claim
137 words
The facsimile transmission system according to claim 4, further including a facsimile receiver comprising means for receiving the acoustic signal and converting that signal to recover the amplitude modulated suppressed carrier electrical signal, means for providing a first signal of the same frequency as the carrier signal of the balanced modulator, means responsive to the occurrence of the recurrent predetermined phase of the suppressed carrier in the recovered signal for causing the phase of the first signal to be brought into phase with the suppressed carrier whereby a phase controlled first signal is obtained, demodulating means responsive to the recovered amplitude modulated suppressed carrier signal and to the phase controlled first signal, the demodulating means providing a demodulated output signal, and marking means responsive to the demodulated output signal for producing a facsimile of the original document.
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) | 1975-06-27 | 1975-12-27 | 1976-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-27 | 1979-12-27 | 1980-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-27 | 1983-12-27 | 1984-06-27 | $7700.00 | Window Closed / Lapsed |