System for transmitting facsimile data in the upper vestigial chrominance sideband of a video signal
First Claim
1. A facsimile machine for injecting an image into a video signal having a bandwidth and chrominance subcarrier, the facsimile machine comprising:
- means for scanning an image to obtain a digital representation of that image;
means responsive to the scanning means for modulating a data carrier based upon the digital representation to provide a modulated signal; and
means for injecting the modulated signal into the video bandwidth at a frequency greater than the chrominance subcarrier.
4 Assignments
0 Petitions
Accused Products
Abstract
The instant application is directed to a cable facsimile machine which implements the upper vestigial chrominance sideband of a standard video signal for data transmission.
Signal processors for permitting the transparent, simultaneous transmission and reception of a data signal in the video bandwidth is disclosed. The signal processor in the transmitter rasterizes the data at the horizontal scanning rate and modulates the data with a data carrier at a non-integral multiple of the horizontal scanning rate to obtain frequency interleaving. The data is transmitted during the active video portion of each video line.
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Citations
33 Claims
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1. A facsimile machine for injecting an image into a video signal having a bandwidth and chrominance subcarrier, the facsimile machine comprising:
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means for scanning an image to obtain a digital representation of that image; means responsive to the scanning means for modulating a data carrier based upon the digital representation to provide a modulated signal; and means for injecting the modulated signal into the video bandwidth at a frequency greater than the chrominance subcarrier. - View Dependent Claims (2, 3, 4)
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5. A facsimile machine for transmission of a facsimile image in a color video signal having a vestigial chrominance sideband and a horizontal scanning rate, the facsimile machine comprising:
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means for scanning an image to obtain a digital representation of that image; means responsive to the scanning means for modulating a data carrier based upon the digital representation to provide a modulated data signal; and means for injecting the modulated data signal into the video signal, wherein the modulation means generates a data carrier at a quarter non-integral multiple of the horizontal scanning rate of the video signal and inhibits the data carrier during the blanking intervals of the video signal. - View Dependent Claims (6, 7)
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8. A method of transmitting an image in a color video signal having a bandwidth and a chrominance subcarrier, the method comprising:
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scanning an image with a facsimile scanner to obtain a digital representation of that image; modulating a data carrier based upon the digital representation of the image to provide a modulated signal; and injecting the modulated signal into the video bandwidth at a frequency greater than the chrominance subcarrier. - View Dependent Claims (9, 10)
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11. A method of transmitting a facsimile image in a color video signal having a vestigial chrominance sideband and a horizontal scanning rate, the method comprising:
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scanning an image to obtain a digital representation of that image; modulating a data carrier at a quarter non-integral multiple of the horizontal scanning rate based upon the digital representation to provide a modulated signal; inhibiting the data carrier during blanking intervals; and injecting the modulated signal into the video signal. - View Dependent Claims (12, 13)
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14. A facsimile machine for adding an image into a rasterized video signal having both an active video portion and blanking intervals and chrominance and luminance portions, the facsimile machine comprising:
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means for scanning an image to obtain a digital representation of that image; means responsive to the scanning means for modulating a data carrier based upon the digital representation to provide a modulated data signal; a combiner to combine the modulated data signal with the video signal during part of the active video intervals to provide a combined signal; and a controller to control the modulating means such that the modulating means provides an unmodulated carrier burst at the start of at least some of the active video intervals. - View Dependent Claims (15, 16, 17, 18)
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19. A facsimile machine for injecting an image into a video signal having an active video portion and blanking intervals, a horizontal scanning frequency and luminance and chrominance spectra, the chrominance spectra having an upper side band and a lower side band, the facsimile machine comprising:
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means for scanning an image to obtain a digital representation of that image; a video processor section including means for attenuating the upper side band of the chrominance spectra and outputting a partially attenuated video signal having blanking intervals; a carrier generator for generating a carrier at a frequency in the upper side band; a data signal section responsive to the digital representation of the image to produce a rasterized data signal having blanking intervals synchronized to the blanking intervals of the video signal; means responsive to the data signal section means for modulating the carrier with the rasterized data signal to provide a modulated signal with the spectral energy almost completely within the attenuated sideband; and an adder for injecting the modulated signal into the partially attenuated video signal at a relatively low level of injection. - View Dependent Claims (20, 21)
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22. A facsimile machine for transmitting an image with a video signal having video blanking intervals of a certain period, the facsimile machine comprising:
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means for scanning an image to obtain a digital representation of that image; means for rasterizing the digital representation to provide a rasterized data signal having blanking intervals a predetermined interval longer than the video blanking intervals; a data carrier generator; and means for combining the video and the rasterized data signal with the data carrier such that each video blanking interval begins substantially at the same time as the data blanking intervals such that the combined signal includes an unmodulated data carrier burst during intervals other than during the blanking interval. - View Dependent Claims (23)
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24. A method for transmitting a facsimile image in a rasterized video signal having both an active video portion and blanking intervals and chrominance and luminance portions, the chrominance portion having a chrominance subcarrier, the method comprising:
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scanning an image to obtain a digital representation of that image; modulating a data carrier based upon the digital representation to provide a modulated data signal; combining the modulated data signal with the video signal during part of the active video intervals to provide a combined signal; and controlling the modulating means such that the modulating means provides an unmodulated carrier burst at the start of at least some of the active video intervals. - View Dependent Claims (25, 26, 27, 28)
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29. A method for injecting a facsimile image into a video signal having an active video portion and blanking intervals, a horizontal scanning frequency and luminance and chrominance spectra, the chrominance spectra having an upper side band and a lower side band, the facsimile machine comprising:
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scanning an image to obtain a digital representation of that image; attenuating the upper side band of the chrominance spectra and outputting a partially attenuated video signal having blanking intervals; generating a carrier at a frequency in the upper side band; producing a rasterized signal responsive to the digital representation of the image having blanking intervals synchronized to the blanking intervals of the video signal; modulating the carrier with the rasterized data signal to provide a modulated signal with the spectral energy almost completely within the attenuated sideband; and injecting the modulated signal into the partially attenuated video signal at a relatively low level of injection. - View Dependent Claims (30, 31)
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32. A method for transmitting a facsimile image with a video signal having video blanking intervals of a certain period and an active video between blanking intervals, the method comprising:
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scanning an image to obtain a digital representation of that image; rasterizing the digital representation to provide a rasterized data signal having blanking intervals a predetermined interval longer than the video blanking intervals; generating data carrier; and combining the video and the rasterized data signal with the data carrier such that each video blanking interval begins substantially at the same time as the data blanking intervals such that the combined signal includes an unmodulated data carrier burst during intervals other than during the blanking interval. - View Dependent Claims (33)
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Specification