Method and apparatus for communicating different categories of data in a single data stream

• US 5,173,900 A
• Filed: 05/17/1991
• Issued: 12/22/1992
• Est. Priority Date: 05/17/1991
• Status: Expired due to Term

• Current Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Original Assignee: General Instrument Corporation (CommScope Holding Company, Inc.)
• Inventors: Miller, Michael R., Kauffman, Marc W., Robbins, Clyde
• Primary Examiner(s): HOM, SHICK C
• Assistant Examiner(s): Jung, Min
• Application Number:
  US07/703,113
• Time in Patent Office: 585 Days
• Field of Search: 370/110.1, 370/94.1, 370/99, 380/13, 380/15, 380/19, 380/20, 380/21, 380/9, 380/10
• US Class Current: 370/349
• CPC Class Codes: H04J 3/16 in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted H04J3/17, H04J3/24 take precedence
• CPC Class Codes: H04N 21/2389 Multiplex stream processing, e.g. multiplex stream encrypting
• CPC Class Codes: H04N 21/439 Processing of audio elementary streams
• CPC Class Codes: H04N 21/8106 involving special audio data, e.g. different tracks for different languages
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

A system for transmitting different categories of data in a single data stream generates program data, receiver control data, and program specific tag data for insertion into a single data stream. Program data is combined with receiver control data to form data groups. Headers are generated containing tag data. Each successive header is combined with a plurality of data groups to form a plurality of units. The data stream is constructed by joining successive units for transmission. A receiver for receiving the data stream detects the receiver control data and the tag data, and recovers the program data in response thereto. A program is reproduced from the recovered program data. The system runs off a master clock having a fixed frequency. Program data is sampled at a first rate that is a function of the master clock frequency. The receiver control data is sampled at a second rate that is a function of the first sampling rate. The tag data is sampled at a third rate that is a function of the second sampling rate. Preferably, the first sampling rate will be an integer factor of the master clock frequency, the second sampling rate will be an integer factor of the first rate and the third sampling rate will be an integer factor of the second rate.

Claims

1. A method for transmitting different categories of data in a single data stream comprising the steps of:

generating program data for insertion into a data stream;

generating a first category of control data for insertion into said data stream;

generating a second category of control data for insertion into said data stream;

combining a set of said program data with a set of said first category of control data to form a data group;

generating a header containing data from said second category of control data;

combining said header with a plurality of said data groups to form a unit; and

constructing said data stream by joining a plurality of successive units for transmission.

2. A method in accordance with claim 1 wherein said second category of control data comprises program specific tag data.

3. A method in accordance with claim 2 wherein said first category of control data comprises non-program specific receiver control data.

4. A method in accordance with claim 3 wherein said tag data identifies the format of the data in said groups.

5. A method in accordance with claim 1 comprising the further steps of:

providing a master clock having a fixed frequency;

sampling said program data for incorporation into said data stream at a first rate that is a function of said master clock frequency;

sampling said first category of control data for incorporation into said data stream at a second rate that is a function of said first sampling rate; and

sampling said second category of control data for incorporation into said data stream at a third rate that is a function of said second sampling rate.

6. A method in accordance with claim 5 wherein:

said master clock frequency has an integer number of cycles per bit of data in said data stream;

said first rate is an integer factor of said master clock frequency;

said second rate is an integer factor of said first rate; and

said third rate is an integer factor of said second rate.

7. A method in accordance with claim 6 wherein said second category of control data comprises tag data that is specific to a particular program in said data stream.

8. A method in accordance with claim 7 wherein said tag data identifies the format of the data in said groups.

9. Apparatus for communicating different categories of digital data to a receiver comprising:

first means for generating a first category of control data for insertion into a data stream;

second means for generating a second category of control data for insertion into said data stream;

third means for generating program data for insertion into said data stream;

means operatively associated with said first and third means for combining a set of said program data with a set of said first category of control data to form a data group;

means operatively associated with said second means for generating a header containing data from said second category of control data;

means for combining said header with a plurality of said data groups to form a unit; and

means for constructing said data stream by joining a plurality of successive units for transmission.

10. Apparatus in accordance with claim 9 wherein said second means generate program specific tag data.

11. Apparatus in accordance with claim 10 wherein said first means generate non-program specific receiver control data.

12. Apparatus in accordance with claim 10 wherein said tag data identifies the format of the data in said groups.

13. Apparatus in accordance with claim 9 further comprising a master clock having a fixed frequency, wherein:

said program data is sampled at a first rate that is a function of said master clock frequency for incorporation into said data stream;

said first category of control data is sampled at a second rate that is a function of said first sampling rate for incorporation into said data stream; and

said second category of control data is sampled at a third rate that is a function of said second sampling rate for incorporation into said data stream.

14. Apparatus in accordance with claim 13 wherein:

said master clock frequency has an integer number of cycles per bit of data in said data stream;

said first rate is an integer factor of said master clock frequency;

said second rate is an integer factor of said first rate; and

said third rate is an integer factor of said second rate.

15. Apparatus in accordance with claim 14 wherein said second means provide tag data that is specific to a particular program in said data stream.

16. Apparatus in accordance with claim 15 wherein said tag data identifies the format of the data in said groups.

17. A receiver for receiving the data stream from the apparatus of claim 9, said receiver comprising:

means for detecting the first and second categories of control data from the received data stream;

means responsive to detected control data for recovering program data from the received data stream; and

means for reproducing a program from the recovered program data.

18. A receiver in accordance with claim 17 further comprising a master clock having a fixed frequency, wherein:

said recovering means sample said program data at a first rate that is a function of said master clock frequency;

said detecting means sample said first category of control data at a second rate that is a function of said first sampling rate; and

said detecting means sample said second category of control data at a third rate that is a function of said second sampling rate.

19. A receiver in accordance with claim 18 wherein:

said master clock frequency has an integer number of cycles per bit of data in said data stream;

said first rate is an integer factor of said master clock fixed frequency;

said second rate is an integer factor of said first rate; and

said third rate is an integer factor of said second rate.

20. A receiver in accordance with claim 17 wherein said program data is digital audio data used to reproduce an audio program.

21. A digital data receiver for receiving a data stream containing successive headers including tag data, with each header followed by a plurality of data groups including program data and receiver control data, said receiver comprising:

first means for detecting receiver control data from successive data groups contained in a received data stream;

second means for detecting tag data from successive headers contained in the received data stream;

means responsive to the detected tag and receiver control data for recovering program data from the received data stream; and

means for reproducing a program from the recovered program data.

22. A data receiver in accordance with claim 21 further comprising a master clock having a fixed frequency, wherein:

said recovering means sample said program data at a first rate that is a function of said master clock frequency;

said first detecting means sample said receiver control data at a second rate that is a function of said first sampling rate; and

said second detecting means sample said tag data at a third rate that is a function of said second sampling rate.

23. A data receiver in accordance with claim 22 wherein:

said first rate is an integer factor of said master clock fixed frequency;

said second rate is an integer factor of said first rate; and

said third rate is an integer factor of said second rate.

24. A data receiver in accordance with claim 23 wherein said program data is digital audio data used to reproduce an audio program.

25. A data receiver in accordance with claim 24 wherein said master clock runs at a rate that provides an integer number of cycles per bit of data in said data stream.

26. A data receiver in accordance with claim 21 further comprising:

means for tuning to different channels to receive different data streams having data groups that may be provided in different formats;

wherein said tag data contains information identifying the data group format for a particular channel for use by said program data recovering means in recovering program data from that channel.