US3624282A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Binary facsimile system
Assignee: PHONOCOPY Inc
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Filing: 1970-07-28
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Granted: 1971-11-30
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Expires: 1990-07-28
Abstract
Abstract A binary-facsimile system which operates by converting the photoelectric analog scan signal to a binary signal the two levels of which represent the black and white data in the portions of the sheet being scanned. The binary signal is processed for partial response transmission and vestigal sideband amplitude modulated on a carrier for transmission in the switched telephone network to obtain increased rate of information transmissions for a given channel bandwidth. The receiver receives the binary signal and prints black or white data in accordance with the binary signal level to form a facsimile reproduction of the original sheet scanned.
Inventors
- 👤 Roy G Salaman
- 👤 John B Picchiottino
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:50
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/32; H04N1/36; H04N1/00095
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
298 words
In apparatus for use in the transmission and reception of facsimile copy of documents and similar materials which can be systematically scanned photoelectrically to obtain an electrical signal with provision for synchronization between similar remote stations, the improvement which permits increased transmission rates when said stations are connected over a narrow band channel such as an ordinary voice telephone line characterized by: quantizing means for converting the photoelectric scan signal into a binary signal having two levels which respectively represent in continuous time correspondence the black and white areas on a document as scanned for transmission by one of said stations, clocking means for clocking said binary signal at a clock rate approximately twice the bandwidth of said channel to produce a corresponding clocked binary signal, means for processing said clocked binary signal into a partial response signal having at least three detectable levels for transmission through said channel at a bit rate approximately twice that of conventional binary-transmission systems where the bit rate is approximately equal to the channel bandwidth, means for modulating a carrier frequency suitable for transmission over said narrow band channel with said partial response signal, means for demodulating a modulated carrier wave received from one of said stations over said channel to recover the modulation signal on said carrier wave, means for partial response decoding said modulation signal to obtain a replica of said binary signal, means for printing a facsimile copy in response to said replica of said binary signal, and means adapted to couple said stations to a voice telephone line either for transmitting modulated signals obtained by scanning a document at the station or for receiving said modulated carrier wave from a remote similar station to print a facsimile copy of a document scanned for transmission at said remote station.
Claim 2
Dependent Claim
298 words
In apparatus for use in the transmission and reception of facsimile copy of documents and similar materials which can be systematically scanned photoelectrically to obtain an electrical signal with provision for synchronization between similar remote stations, the improvement which permits increased transmission rates when said stations are connected over a narrow band channel such as an ordinary voice telephone line characterized by: quantizing means for converting the photoelectric scan signal into a binary signal having two levels which respectively represent in continuous time correspondence the black and white areas on a document as scanned for transmission by one of said stations, clocking means for clocking said binary signal at a clock rate approximately twice the bandwidth of said channel to produce a corresponding clocked binary signal, means for processing said clocked binary signal into a partial response signal having at least three detectable levels for transmission through said channel at a bit rate approximately twice that of conventional binary-transmission systems where the bit rate is approximately equal to the channel bandwidth, means for modulating a carrier frequency suitable for transmission over said narrow band channel with said partial response signal, means for demodulating a modulated carrier wave received from one of said stations over said channel to recover the modulation signal on said carrier wave, means for partial response decoding said modulation signal to obtain a replica of said binary signal, means for printing a facsimile copy in response to said replica of said binary signal, and means adapted to couple said stations to a voice telephone line either for transmitting modulated signals obtained by scanning a document at the station or for receiving said modulated carrier wave from a remote similar station to print a facsimile copy of a document scanned for transmission at said remote station.
Claim 3
Dependent Claim
24 words
Apparatus according to claim 1 in which said means for processing said clocked binary signal into a partial response signal is a filter means.
Claim 4
Dependent Claim
89 words
Apparatus according to claim 2 in which said means for modulating a carrier frequency includes a carrier oscillator having a frequency near the upper limit of the pass band of said narrow band channel, an amplitude modulator for modulating said carrier with said partial response signal; and a vestigial sideband filter for band-limiting the output of said modulator; said carrier oscillator, modulator and vestigial sideband filter producing a frequency inverted and shifted signal corresponding to said partial response signal modified to utilize substantially the whole bandwidth of said channel.
Claim 5
Dependent Claim
66 words
Apparatus according to claim 3 in which said coupling means comprises magnetic couplings to the earpiece of a telephone handset and includes two coupling coil means the coils of which are positioned to encircle the internal coil of said earpiece and be substantially coplanar therewith, the coil means used for coupling received signals from said telephone line including at least two coils connecting for hum-bucking operation.
Claim 6
Dependent Claim
39 words
Apparatus according to claim 2 in which said clocking means includes means for producing a clocked binary signal which changes state for bits of one of said levels and does not change state for bits of the other level.
Claim 7
Dependent Claim
133 words
Apparatus according to claim 5 in which said means for processing said clocked binary signal comprises: a. a premodulation low-pass filter for converting said clocked binary signal into said partial response signal, b. a carrier oscillator of frequency near the upper frequency limit of said channel, c. a baseband balanced amplitude modulator for modulating said cArrier with said partial response signal, d. a vestigial sideband filter for band limiting the output of said modulator, and e. a transmitting transversal filter for said vestigial sideband signal, said filters and modulator producing a frequency shifted and inverted signal corresponding to said clocked binary signal modified to utilize substantially the whole bandwidth of said channel and compensated for the amplitude and phase distortion introduced by the transfer function of the equipment through which the signal passes.
Claim 8
Dependent Claim
54 words
Apparatus according to claim 6 and including a receiving transversal filter having a transfer function to compensate for the amplitude and phase distortion introduced by said channel on the vestigial sideband signal received from a remote similar unit, and means for passing the modulated carrier coupled from said channel to said receiving transversal filter.
Claim 9
Dependent Claim
30 words
Apparatus according to claim 6 and including means for phase locking said precision local oscillator with the bit rate detected from the modulated carrier received from a remote similar unit.
Claim 10
Dependent Claim
77 words
Apparatus according to claim 8 in which said scanning means and said printer include: a. means for relatively driving a sheet at a uniform rate transverse to a scanning line position; b. motor means for driving a scanning head repetitively across said sheet at said scan line position; c. means for deriving a submultiple frequency from said precision local oscillator; and d. means for controlling the speed of said motor means in accordance with said submultiple frequency.
Claim 11
Dependent Claim
100 words
Apparatus according to claim 2 including: a. means for phase locking said precision local oscillator with the bit rate detected from the modulated carrier received from a remote similar unit; b. means in said scanning means and said printer for relatively driving a sheet at a uniform rate transverse to a scanning line position; c. motor means for driving a scanning head repetitively across said sheet at said scan line position; d. means for deriving a submultiple frequency from said precision local oscillator; and e. means for controlling the speed of said motor means in accordance with said submultiple frequency.
References Cited (Backward Citations)
US3313884A
Cited
US3453383A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-29 | 1975-05-31 | 1975-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-29 | 1979-05-31 | 1979-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-29 | 1983-05-31 | 1983-11-30 | $7700.00 | Window Closed / Lapsed |