System and method for inserting and recovering an add-on data signal for transmission with a video signal

A system for transmitting a data signal with a video signal, comprising:

• a first filter receiving the data signal and producing a filtered signal having a plurality of spectral peaks with spacing corresponding to spacing of an unused portion of the frequency spectrum of the video signal, said data signal being unrelated to the video signal;
• a modulator element modulating a single unmodulated carrier frequency with said filtered signal to produce a modulated filtered signal, said carrier frequency being selected to modulate said filtered signal into said unused portion of the frequency spectrum of the video signal to produce a modified video signal containing said modulated filtered signal with said filtered signal inserted into said unused portion of the frequency spectrum of the video signal;
• a signal separator processing, said modified video signal to recover said filtered signal;
• and
• a second filter receiving said recovered filtered signal from said signal separator to recover the data signal from said recovered filtered signal, whereby the data signal is inserted into said unused portion of the frequency spectrum of the video signal and subsequently recovered from the video signal.

A system for recovering a data signal inserted into an unused portion of the frequency spectrum of an unrelated video signal, the data signal being filtered to generate a filtered signal having a plurality of spectral peaks with a spacing corresponding to spacing in an unused portion of the frequency spectrum of the video signal and modulated with a single unmodulated carrier frequency to generate a modulated data signal, the system comprising:

• a signal separator separating the modulated data signal from the unused portion of the frequency spectrum of the video signal;
• a demodulator coupled to said signal separator and demodulating the modulated data signal to recover the filtered signal, said demodulator having a single carrier frequency with a predetermined phase and a carrier frequency selected to correspond to the unused portion of the frequency spectrum of the video signal;
• and
• a receiver filter receiving said filtered signal from said demodulator to recover the data signal from the filtered signal, said recovered data signal being uncorrelated to the video signal, whereby the data signal is inserted into the unused portion of the frequency spectrum of the video signal and subsequently recovered from the video signal.

A method for transmitting a data signal with a video signal, comprising the steps of:

• filtering the data signal to produce a filtered signal having a plurality of spectral peaks with spacing corresponding to spacing of an unused portion of the frequency spectrum of the video signal, the data signal being independent of the video signal;
• modulating a single unmodulated carrier frequency with said filtered signal to produce a modulated filtered signal, said carrier frequency being selected to modulate said filtered signal into said unused portion of the frequency spectrum of the video signal to produce a modified video signal containing said modulated filtered signal with said filtered signal inserted into said unused portion of the frequency spectrum of the video signal;
• separating said filtered signal from said modified video signal;
• and
• inverse filtering said filtered signal separated by said signal separator to recover the data signal from said filtered signal.

A method for recovering a data signal inserted into an unused portion of the frequency spectrum of an unrelated video signal, the data signal being filtered to generate a filtered signal having a plurality of spectral peaks with a spacing corresponding to spacing in an unused portion of the frequency spectrum of the video signal and modulated with a single unmodulated carrier frequency to generate a modulated data signal, the method comprising the steps of:

• separating the modulated data signal from the unused portion of the frequency spectrum of the video signal;
• demodulating the modulated data signal separated from the unused portion of the spectrum of the video signal to recover the filtered signal, said step of demodulating using a single carrier frequency having a predetermined phase with said carrier frequency selected to correspond to said unused portion of the frequency spectrum of the video signal;
• and
• inverse filtering the filtered signal following said step of demodulating to recover the data signal from the filtered signal, said recovered data signal being uncorrelated to the video signal.