Video scrambling technique for multiplexed analog component formats

• US 4,620,224 A
• Filed: 04/03/1985
• Issued: 10/28/1986
• Est. Priority Date: 04/03/1985
• Status: Expired due to Term

• Current Assignee: COMSAT Corporation (Reorganized ISA SA)
• Original Assignee: Communications Satellite Corporation (Reorganized ISA SA)
• Inventors: Lee, Lin-nan, Redman, Mark D.
• Primary Examiner(s): Buczinski, S. C.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/719,200
• Time in Patent Office: 573 Days
• Field of Search: 358/114, 358/119, 358/123, 358/122, 358/12
• US Class Current: 380/214
• CPC Class Codes: H04N 7/1696 by changing or reversing the order of active picture signal portions

Abstract

A method for scrambling a television signal for use with a multiplexed analog component (MAC) format employs a three digital bit code for each horizontal line of the picture. The bits identify the position of the luminance and chrominance information of the signal for every line of the television picture and whether the information is to be scanned from left to right or right to left.

Claims

1. A method for scrambling a television signal comprising the steps of:

formatting a television signal into a data portion and a video portion wherein said video portion has chrominance information and luminance information which portions are scanned for each horizontal line of a television picture;

writing said luminance portion and chrominance portion into luminance and chrominance memories, respectively;

encoding said data portion to represent the directions in which the chrominance information and luminance information are to be read; and

encoding said data portion to represent the position of the chrominance information relative to the luminance information in the video portion.

7. The method of claims 1, 2, 3 or 4 wherein the relative position of said luminance portion and said chrominance portion is such that said luminance portion precedes said chrominance portion in a given scan line.

8. The method of claims 1, 2, 3 or 4 wherein the relative position of said luminance portion and said chrominance portion is such that said chrominance portion precedes said luminance portion for a given scan line.

2. In a multiplexed analog component television signal format including chrominance and luminance information which is scanned to produce a television picture, the method of scrambling said signal by inserting a data portion at the beginning of each horizontal scan line of a television picture comprising the steps of:

encoding two bits of the data portion to identify the respective direction which the chrominance and luminance information is scanned; and

encoding a third bit of said data portion to represent the position of the chrominance portion relative to the luminance portion.

3. A method for formatting a multiplexed analog component television scan line signal having a luminance portion and a chrominance portion comprising the steps of:

separating said luminance and chrominance portions for every scan line of the television signal;

writing said luminance and chrominance portions into a luminance portion memory and a chrominance portion memory, respectively;

scanning the luminance portion memory in a preselected direction;

scanning the chrominance portion memory in a preselected direction;

providing a code at the beginning of each scan line which identifies the directions in which the luminance and chrominance portion memories are scanned and which identifies the relative position of the luminance and chrominance portion for a given scan line.

5. A method as set forth in claim 3 or claim 4 wherein the preselected direction that said luminance portion memory is scanned is different from the preselected direction that said chrominance portion is scanned.

6. The method as set forth in claims 3 or 4 wherein the presected direction that said luminance portion memory is scanned is the reverse of the preselected direction that said chrominance portion memory is scanned.

4. A method for formatting a multiplexed analog component television scan line signal having a luminance portion and a chrominance portion comprising the steps of:

separating said luminance and chrominance portions for every scan line of the television signal;

writing said luminance portion and said chrominance portion into a luminance portion memory and a chrominance portion memory, respectively;

scanning the luminance portion memory in a preselected direction;

scanning the chrominance portion memory in a preselected direction;

providing a pseudo-random number code at the beginning of each scan line which identifies the relative positions of the luminance and chrominance portions for a given scan line.