Gray scale sync video processing system

• US 4,295,155 A
• Filed: 06/08/1979
• Issued: 10/13/1981
• Est. Priority Date: 06/08/1979
• Status: Expired due to Term

• Current Assignee: PPG Industries Ohio Incorporated (Nouryon BV)
• Original Assignee: International Telephone & Telegraph Corp. (ITT, Inc.)
• Inventors: Jarger, Harold F., Sassler, Marvin L.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/047,188
• Time in Patent Office: 858 Days
• Field of Search: 358/142, 358/145, 358/148, 358/151, 358/153, 358/160, 358/165, 358/186, 358/114, 358/120, 358/17, 358/21, 358/12, 358/19
• US Class Current: 348/470
• CPC Class Codes: H04N 7/084 with signal insertion during the horizontal blanking interval only
• CPC Class Codes: H04N 7/167 Systems rendering the television signal unintelligible and subsequently intelligible

Abstract

The blacker-than-black sync pulse of a standard video signal is replaced by a gray scale sync to increase picture signal, permit audio multiplexing and allow security phase inversion by means of encoder and decoder circuitry including a sync stripper, gate and timing generator, audio processor, phase code generator, color reference regenerator, blank and summing amplifier, and phase reversal amplifier.

Claims

1. A video processing system, comprising:

a source of video signals of a given narrow bandwidth;

means to transmit said video signals;

means to receive said video signals;

said video signals including a picture component and a blanking component;

first circuitry connected to said source and said transmission means for eliminating said blanking component and increasing said picture component for transmission; and

wherein said picture component is increased by at least twenty-five percent of the composite peak-to-peak deviation of said signals;

a source of audio signals and wherein said first circuitry mixes said audio signals into said video signals; and

second circuitry connected to said receive means.

2. The system of claim 1, wherein said first circuitry increases the picture signal-to-noise ratio by 2.8 dB.

3. The system of claim 1, wherein said bandwidth remains constant.

4. The system of claim 3, wherein said bandwidth is decreased and the quality of said video signals remains constant.

5. The system of claim 1, wherein said first circuitry includes blanking means replacing said blanking component with synchronization means.

6. The system of claim 5, wherein said synchronization means is between the white and black extremities of said video signals.

7. The system of claim 5, wherein said synchronization means includes a plurality of pulses.

8. The system of claim 7, wherein said first circuitry includes phase reversal means and adjacent ones of said pulses may be phase inverted with respect to each other.

9. The system of claim 7, wherein said first circuitry includes color reference means and each of said pulses includes color reference information.

10. The system of claim 9, wherein said color information is at one edge of said pulses.

11. The system of claim 7, including a source of audio signals and wherein said first circuitry includes audio processing means and each of said pulses includes information from said audio signals.

12. The system of claim 11, wherein said information is pulse-width modulated onto one edge of said pulses and said bandwidth remains constant.

13. The system of claim 7, wherein said blanking component includes a horizontal sync and one edge of the first of said pulses is used for horizontal synchronization.

14. The system of claim 1, wherein said first circuitry includes phase reversal means and the polarity of alternate ones of said picture components is reversed.

15. The system of claim 14, wherein said polarity reversal produces a symmetrical spectrum around the RF carrier frequency of said video signals.

16. The system of claim 1, wherein said blanking component is regenerated in said second circuitry.

17. The method of processing a video signal with a picture component and a blanking component including the steps of:

eliminating the blanking component;

increasing the picture component simultaneously with said elimination step;

inserting synchronization in the video signal after the elimination step;

multiplexing audio information onto the video signal simultaneously with said synchronization step;

transmitting the resulting video signal.

18. The method of claim 17, including the step of inserting color information into the synchronization.

19. The method of claim 17, wherein the synchronization is placed between the white and black extremities of the video signal.

20. The method of claim 17, including the step of reversing polarity of alternating picture components.

21. The method of claim 20, including the step of producing a symmetrical spectrum around the RF carrier frequency of the video signal simultaneously with said reversal step.

22. The method of claim 17, including the step of regenerating the blanking component after said receiving step.

23. Video processing apparatus comprising:

a source of video signals of a given bandwidth;

means to transmit said signals;

said video signals including a picture component and a blanking component;

blanking means replacing said blanking component with synchronization means including a plurality of pulses;

a source of audio signals and wherein said audio signals are mixed into said video signals and said bandwidth remains constant; and

increasing said picture component for transmission.

24. The apparatus of claim 23, wherein said synchronization means is midway between the white and black extremities of said video signals.

25. The apparatus of claim 23, further comprising phase reversal means whereby adjacent ones of said pulses may be phase inverted with respect to each other.

26. The apparatus of claim 23, wherein the leading edge of said pulses includes color information.

27. The apparatus of claim 23, wherein said audio signals that are pulse-width modulated onto the trailing edge of said pulses and said bandwidth remains constant.

28. The apparatus of claim 23, wherein said blanking component creates a horizontal sync and the leading edge of the first of said pulses is in phase with said horizontal sync.

29. The apparatus of claim 23, wherein said blanking means includes phase reversal means and the polarity of alternate ones of said picture components is reversed.

30. The method of processing a video signal with a picture component and a blanking component including the steps of:

eliminating the blanking component;

increasing the picture component simultaneously with said elimination step;

inserting synchronization in the video signal after the elimination step;

multiplexing audio information onto the video signal simultaneously with said synchronization step;

inserting color information into the synchronization;

placing the synchronization midway between the white and black extremities of the video signal;

reversing the polarity of alternating picture components; and

transmitting the resulting video signal.

31. Video processing apparatus, comprising means for receiving video signals with modulated audio information, first circuitry connected to said means for extracting said information, second circuitry connected to said means for inserting a blanking component and decreasing the picture component in said signals.

32. The apparatus of claim 31, including third circuitry for reversing the phase of said signals.

33. The apparatus of claim 31, including fourth circuitry for generating a reference color signal.

34. The apparatus of claim 31, wherein said blanking component includes a horizontal sync pulse and a color burst.

35. The method of processing a video signal with audio information, comprising the steps of extracting said information, inserting a blanking component in said signal, and simultaneously with said insertion decreasing the picture component in said signal.

36. The method of claim 35, including the step of correcting the video phase of said signal prior to said extraction.

37. The method of claim 35, including the step of generating a reference color signal prior to said insertion.

38. The method of claim 37, wherein said component includes a blank sync and color burst.

39. The method of processing a video signal having a limited bandwidth and having a picture component and a blanking component including the steps of:

eliminating the blanking component,

increasing the picture component to more fully utilize the limited bandwidth,

inverting each alternate line of the video signal to provide a more uniform frequency distribution centered about the carrier hence providing better use of threshold extension and suitable for use with a narrow bandwidth while improving the security of the transmission,

providing a horizontal blanking interval midway between the white and black extremities of the video signal,

providing a pulse width modulated audio signal in the horizontal blanking interval,

transmitting the resulting signal.