Data with video transmitter

A processor for adding a data signal to a video signal having an active video portion and blanking intervals, a horizontal scanning frequency and a luminance and chrominance spectra, the chrominance spectra having an upper side band and a lower side band, the processor comprising:

• 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 data signal to produce an output rasterized data signal having blanking intervals synchronized to the blanking intervals of the video signal;
• a modulator for modulating the carrier with the rasterized data signal such that the spectral energy of the output of the modulator lies almost completely within the attenuated sideband;
• and
• an adder for injecting the modulated carrier into the partially attenuated video signal at a relatively low level of injection.

A processor for isolating a rasterized, modulated data signal in a video signal having a horizontal scanning rate, the rasterized data signal lying within a portion of the frequency band for the video signal and the data signal having been injected into the active portions of the video signal by modulating a data carrier based upon the data to be transmitted and at least some portions of the data carrier being unmodulated to comprise a phase synchronization marker in the video signal, the processor comprised:

• a filter to attenuate those portions of the spectra not containing the data signal;
• a phase adjustable data carrier generator for generating a data carrier;
• a demodulator responsive to the carrier and the filtered data signal;
• detection means for detecting the phase synchronizer marker;
• and
• means for altering the phase of the carrier generator in response to the detected marker.

A method for receiving data information combined with both the chrominance and luminance information of a rasterized signal having an active video interval, the data information having been modulated with a transmitter data carrier and including a phase marker comprising an unmodulated burst of the data carrier injected in the active video interval, the method comprising:

• generating a receiver data carrier at substantially the same frequency as the transmitter data carrier;
• demodulating the information from the signal;
• locating the marker information in the active video line;
• and
• altering the phase of the data carrier in response to the phase marker.

A method for transmitting a data signal with a video signal having video blanking intervals of a certain period, the data and video signals being substantially uncorrelated, the method comprising:

• detecting the timing of the blanking intervals;
• rasterizing the data signal to provide data blanking intervals in the rasterized data signal, the data blanking intervals being a predetermined interval longer than the video blanking intervals;
• generating a 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.

A method for separating a data signal that has been injected at a remote location into the bandwidth of a video signal having parameters including blanking intervals at a sync rate with active video lines between the blanking intervals, the injection including modulating a remote data carrier having a frequency and a phase and injecting at predetermined intervals in the signal an unmodulated remote data carrier burst having a phase, the method comprising:

• monitoring at least one of the parameters of the video signal;
• determining the relative timing of the data carrier burst based upon the monitoring of the at least one parameter;
• determining in response to the video signal during the data carrier bursts the relative phase of the data carrier;
• and
• generating a local data carrier in a predetermined phase relationship with the phase of the remote data carrier.

A method for adding a data signal to a video signal having an active video portion and blanking intervals, a horizontal scanning frequency and a luminance and chrominance spectra, the chrominance spectra having an upper side band and a lower side band, the processor comprising:

• attenuating the upper side band of the chrominance spectra and outputting a partially attenuated video signal having blanking intervals;
• generating a data carrier at a frequency in the upper side band;
• providing an output rasterized data signal having blanking intervals synchronized to the blanking intervals of the video signal;
• modulating the data carrier with the rasterized data signal such that the spectral energy of the output of the modulator lies almost completely within the attenuated sideband;
• and
• adding the modulated carrier into the attenuated video signal at a relatively low level of injection.