Expanded information capacity for existing communication transmission systems

• US 20040100588A1
• Filed: 08/09/2002
• Published: 05/27/2004
• Est. Priority Date: 04/17/1998
• Status: Active Grant

• Current Assignee: Callahan Cellular LLC (Intellectual Ventures LLC)
• Original Assignee: Dotcast Incorporated
• Inventors: Ciciora, Walter S., Hartson, Ted E., Dickinson, Robert V. C.
• Granted Patent: US 7,333,153 B2
• Time in Patent Office: Days
• US Class Current: 348/608
• CPC Class Codes: H04N 21/426 Internal components of the client ; Characteristics thereof H04N5/44 takes precedence
• CPC Class Codes: H04N 7/08 Systems for the simultaneous or sequential transmission of more than one television signal, e.g. additional information signals, the signals occupying wholly or partially the same frequency band , e.g. by time division H04N7/007 takes precedence
• CPC Class Codes: H04N 7/0803 using frequency interleaving, e.g. with precision offset

Abstract

A system for transmitting digital programming includes a program source providing digital information, circuitry for modulating the digital information onto a visual carrier modulated with analog television programming, and a visual transmitter coupled to the modulating circuitry. Using a phase modulation method, the system phase modulates the digital information onto a visual carrier, reduces the baseband frequencies of the phase modulated visual carrier, and amplitude modulates the phase-modulated video carrier onto a video signal. The amplified and encoded video signal are combined with an amplified sound signal and transmitted. Using an additive method, the system modulates the sidebands of the video carrier with the digital information and amplitude modulates the video signal onto the video carrier. The data-modulated sidebands are phase-shifted such that they will be in quadrature with the amplitude-modulated video signal. The system combines the amplitude-modulated video carrier and the data-modulated quadrature sidebands. With a blended multiplicative/additive method, the system provides phase modulation and quadrature sideband addition to provide an optimized result.

Claims

1. A system for transmitting multilevel digital information from at least one program source, the system comprising:

circuitry for modulating the multilevel digital information onto a carrier;

circuitry for modulating the carrier with analog television programming; and

a visual transmitter coupled to the modulating circuitry.

2. The system for transmitting digital programming, as recited in claim 1, wherein the circuitry for modulating the multilevel digital information onto the carrier further comprises:

a phase modulator for phase modulating the multilevel digital information onto the visual carrier, the phase modulation creating a plurality of sidebands about the phase modulated carrier;

circuitry for adjusting amplitudes and phases of the sidebands.

3. The system for transmitting digital programming, as recited in claim 2, wherein the circuitry for adjusting amplitudes and phases further comprises:

a Nyquist filter;

a first oscillator;

a first mixer coupled to the Nyquist filter and the first oscillator;

a first bandpass filter coupled to the mixer;

a second oscillator;

a second mixer coupled to the first bandpass filter and the second oscillator; and

a second bandpass filter coupled to the second mixer.

4. The system for transmitting multilevel digital information from at least one program source, as recited in claim 1, wherein the circuitry for modulating the multilevel digital information onto the carrier further comprises:

a phase modulator for phase modulating the multilevel digital information onto a first carrier, the modulating creating a first plurality of sidebands about the first modulated carrier;

circuitry for adjusting amplitudes and phases of the first plurality of sidebands;

circuitry for amplitude modulating a composite video signal onto the first carrier, the modulation creating a television visual carrier;

circuitry for modulating the multilevel digital information onto a optionally suppressed second carrier in quadrature to the visual carrier, the modulation of the optionally suppressed second carrier creating a second plurality of sidebands about the second modulated carrier;

circuitry for adjusting amplitudes and phases of the second plurality of sidebands; and

circuitry for combining the second plurality of sidebands with the television visual carrier.

5. The system for transmitting multilevel digital information, as recited in claim 4, further comprising:

a second program source providing second multilevel digital information; and

circuitry for modulating the second multilevel digital information onto the second carrier.

6. A system for transmitting multilevel digital information from a program source, the system comprising:

circuitry for creating a visual carrier modulated with analog television programming;

circuitry for creating a second carrier in quadrature to the visual carrier;

circuitry for modulating the multilevel digital information onto the second carrier, the modulation creating a plurality of sidebands about the modulated optionally suppressed second carrier;

circuitry for adjusting the amplitude and phase of the second plurality of sidebands;

level control circuitry for adjusting strength of the modulated second carrier and the plurality of sidebands;

circuitry for combining the plurality of sidebands with the visual carrier; and

a visual transmitter coupled to the combining circuitry.

7. The system for transmitting multilevel digital information, as recited in claim 6, further comprising circuitry for reducing visibility in a television-displayed picture resulting from the combined sidebands and the visual carrier, the visibility reducing circuitry processing the multilevel digital information prior to modulation.

8. The system for transmitting multilevel digital information, as recited in claim 6, further comprising:

circuitry for creating an abatement signal; and

circuitry for injecting the abatement signal into the visual carrier.

9. The system for transmitting multilevel digital information, as recited in claim 8, wherein the circuitry for creating an abatement signal further comprises:

a plurality of waveform shaping circuits;

a level control circuit coupled to the plurality of waveform shaping circuits;

a first delay circuit coupled to the level control circuit;

a second delay circuit coupled to the circuitry for creating a visual carrier; and

a combiner coupled to the second delay circuit.

10. A system for transmitting multilevel digital information from at least one program source, the system comprising:

circuitry for creating a visual carrier modulated with analog television programming;

circuitry for creating a second carrier in quadrature to the visual carrier;

circuitry for modulating multilevel digital information onto the second carrier, the modulation creating a plurality of sidebands about the modulated second carrier;

circuitry for adjusting the amplitude and phase of the second plurality of sidebands;

level control circuitry for adjusting strength of the modulated second carrier and the plurality of sidebands;

circuitry for combining the plurality of sidebands with the visual carrier; and

a visual transmitter coupled to the modulating circuitry;

a second digital program source providing second multilevel digital information;

circuitry for modulating the second multilevel digital information onto an aural carrier modulated with television audio; and

an aural carrier coupled to the circuitry for modulating the second multilevel digital information.

11. The system for transmitting multilevel digital information, as recited in claim 10, wherein the circuitry for modulating the second multilevel digital information further comprises:

a multilevel data source;

a baseband sound source;

a sound frequency modulation modulator coupled to the baseband sound source;

an amplitude modulation data modulator having an input coupled to an output of the sound frequency modulation modulator and a second input coupled to the multilevel data source;

a bandpass filter coupled to the amplitude modulation data modulator; and

a sound transmitter coupled to the bandpass filter.

12. The system for transmitting multilevel digital information, as recited in claim 11, wherein the bandpass filter has a vestigial sideband characteristic for creating asymmetrical sideband pairs.

13. A system for receiving digital programming within at least one of a visual carrier and an aural carrier, the system comprising:

a video receiver adapted to receive a desired frequency band containing the visual carrier;

a first data demodulator coupled to the receiver; and

a first data extractor coupled to the data demodulator.

14. The system for receiving digital programming, as recited in claim 13, further comprising:

an audio receiver adapted to receive a desired frequency band containing an aural carrier having second digital programming;

a second data demodulator coupled to the audio receiver; and

a second data extractor coupled to the data demodulator.

15. The system for receiving digital programming, as recited in claim 13, wherein the system is incorporated into a television receiver.

16. The system for receiving digital programming, as recited in claim 13, wherein the second data demodulator further comprises:

a bandpass filter; and

an amplitude modulation detector coupled to the bandpass filter.

17. The system for receiving digital programming, as recited in claim 13, wherein the first data extractor further comprises:

a plurality of level slicers each with one input coupled to a data demodulator, a second input coupled to a clock circuit, and a third input coupled to a different threshold voltage;

a plurality of logic circuits coupled to the plurality of level slicers, the logic circuits converting outputs of the plurality of level slicers into binary logic values; and

a plurality of non-equally spaced threshold voltages to provide for differential noise immunity for multiple data signals.

18. The system for receiving digital programming, as recited in claim 16, further comprising:

a baseband equalizer,

wherein the bandpass filter is implemented following detection of the spectrum by the baseband equalizer.

19. The system for receiving digital programming, as recited in claim 13, wherein the first data demodulator further comprises:

a mixer;

a phase shifter coupled to a first input of the mixer;

an amplifier coupled to a second input of the mixer;

a phase locked loop coupled to the phase shifter;

a bandpass filter coupled to the phase locked loop; and

a television receiver having an intermediate frequency amplifier coupled to the bandpass filter.

20. The system for receiving digital programming, as recited in claim 13, wherein the first data demodulator further comprises:

a combiner;

a first mixer coupled to the combiner;

a high pass filter coupled to the combiner;

a second mixer coupled to the combiner;

a phase locked loop coupled to the second mixer;

a receiver having an intermediate frequency amplifier tuned to the frequency band containing the visual carrier, the amplifier being coupled to the phase locked loop;

an amplifier coupled to the first mixer, the second mixer, and an output of the intermediate frequency amplifier;

a phase shifter coupled to the phase locked loop, the amplifier and the first mixer.

21. The system for receiving digital programming, as recited in claim 14, wherein the first data demodulator further comprises a vertical-blanking-interval multilevel signal detector.

22. The system for receiving digital programming, as recited in claim 14, further comprising an output device that outputs the first and second digital programming.

23. The system for receiving digital programming, as recited in claim 22, wherein the output device further comprises an MPEG compressed video decoder.

24. The system for receiving digital programming, as recited in claim 22, wherein the output device further comprises a Web appliance.

25. The system for receiving digital programming, as recited in claim 22, wherein the output device further comprises a personal computer.

26. The system for receiving digital programming, as recited in claim 22, wherein the output device further comprises an analog television receiver.

27. A system for transmitting multilevel digital information from a program source, the system comprising:

circuitry for creating a visual carrier modulated with analog television programming;

circuitry for transmitting a directory of information within the modulated visual carrier;

circuitry for creating a second carrier in quadrature to the visual carrier;

circuitry for modulating the multilevel digital information onto the second carrier, the modulation creating a plurality of sidebands about the modulated second carrier;

circuitry for adjusting the amplitudes and phases of the plurality of sidebands;

level control circuitry for adjusting strength of the modulated second carrier and the plurality of sidebands;

circuitry for combining the plurality of sidebands with the visual carrier; and

a visual transmitter coupled to the combining circuitry.

28. The system for transmitting digital programming, as recited in claim 27, wherein the directory identifies:

data types of the multilevel digital information; and

locations of a plurality of segments of the multilevel digital information.

29. The system for transmitting digital programming, as recited in claim 27, wherein the directory identifies data carried in the visual carrier.

30. The system for transmitting digital programming, as recited in claim 27 further comprising a digital compression unit that removes redundancy from the multilevel digital information.

31. A system for transmitting digital programming comprising:

a first data source;

a second data source;

a television signal source;

a reference oscillator;

a band pass filter;

a first mixer coupled to the band pass filter;

a reference oscillator coupled to the first mixer;

a first combiner coupled to the first mixer;

a double balanced modulator coupled to the first combiner;

an aural data encoder coupled to the first data source;

an aural intermediate frequency amplifier coupled to the double balanced modulator;

a first directional coupler having a tap output coupled to the aural intermediate frequency amplifier;

a second directional coupler having a pass-through output coupled to the first directional coupler;

a second mixer coupled to the second directional coupler, the television signal source and the reference oscillator;

a second combiner;

a third directional coupler having a pass-through output coupled to the second combiner;

a visual intermediate frequency amplifier coupled to the third directional coupler and a pass-through output of the first directional coupler;

an amplitude modulation modulator coupled to the second combiner;

a phase locked loop coupled to the amplitude modulation modulator and a tap output of the second directional coupler;

a visual data encoder coupled to the second combiner and the second data source;

a phase shifter coupled to the visual data encoder; and

a second data source.

32. A method for transmitting multilevel digital information from at least one program source, the system comprising the steps of:

modulating the multilevel digital information onto a carrier;

modulating the carrier with analog television programming; and

transmitting the modulated carrier.

33. The method for transmitting multilevel digital information, as recited in claim 32, further comprising the steps of:

phase modulating the multilevel digital information onto the visual carrier, the phase modulation creating a plurality of sidebands about the phase modulated carrier;

adjusting amplitudes and phases of the sidebands.

34. The method for transmitting multilevel digital information, as recited in claim 32, wherein the step of modulating the multilevel digital information onto a carrier further comprises the steps of:

phase modulating the multilevel digital information onto a first carrier, the modulating creating a first plurality of sidebands about the first modulated carrier;

adjusting amplitudes and phases of the first plurality of sidebands;

amplitude modulating a composite video signal onto the first carrier, the modulation creating a television visual carrier;

modulating the multilevel digital information onto a second carrier in quadrature to the visual carrier, the modulation of the second carrier creating a second plurality of sidebands about the second modulated carrier;

adjusting amplitude and phases of the second plurality of sidebands; and

combining the first and second plurality of sidebands with the television visual carrier.

35. A method for transmitting multilevel digital information from at least one program source, the method comprising the steps of:

creating a visual carrier modulated with analog television programming;

creating a second carrier in quadrature to the visual carrier;

modulating the multilevel digital information onto the second carrier, the modulation creating a plurality of sidebands about the modulated second carrier;

adjusting amplitudes and phases of the second plurality of sidebands;

adjusting strength of the modulated second carrier and the plurality of sidebands;

combining the plurality of sidebands with the visual carrier; and

transmitting the combined sidebands and visual carrier.