Method for creating a system clock in a receiver device and corresponding receiver device

• US 20060176963A1
• Filed: 05/30/2003
• Published: 08/10/2006
• Est. Priority Date: 06/12/2002
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Barthel, Joerg, Mittendorf, Christian
• Granted Patent: US 7,903,774 B2
• Time in Patent Office: Days
• US Class Current: 375/240.280
• CPC Class Codes: H04N 21/4305 Synchronising client clock from received content stream, e.g. locking decoder clock with encoder clock, extraction of the PCR packets arrangements for synchronising receiver with transmitter by comparing receiver clock with transmitter clock H04L7/0012; arrangements for synchronising receiver with transmitter wherein the receiver takes measures against momentary loss of synchronisation H04L7/0083
• CPC Class Codes: H04N 21/43072 of multiple content streams on the same device

Abstract

According to a method for generating a system time clock in a receiving device for digital packetized elementary data streams (E), the packetized elementary data streams (E) being generated in a transmitting device by sampling at a sampling frequency (f_sample) synchronized by a system time clock of the transmitting device, the sampling frequency (f_sample) of one data stream is determined in the receiving device, and the program clock reference counter is synchronized with the data stream'"'"'s sampling frequency.

Claims

1-13. -13. (canceled)

14. A method for generating a system time clock counter in a receiving device for digital data streams, comprising:

generating the digital data streams in a transmitting device by sampling at a sampling frequency synchronized by a system time clock in the transmitting device;

determining the sampling frequency of one of the data streams in the receiving device; and

synchronizing the system time clock counter with the determined sampling frequency of the one of the data streams.

15. The method as recited in claim 14, further comprising:

setting an increment of the system time clock counter; and

determining the increment from a ratio between a program clock reference and the sampling frequency.

16. The method as recited in claim 15, further comprising:

setting the increment to a constant value based on a nominal sampling frequency.

17. The method as recited in claim 15, further comprising:

comparing an instantaneous presentation time stamp of a packetized elementary data stream used to determine the sampling frequency with an instantaneous count of the system time clock counter; and

correcting the increment of the system time clcok counter according to a comparison result.

18. The method as recited in claim 14, further comprising:

determining the sampling frequency from the data stream having the greatest sampling frequency of any of the available data streams.

19. The method as recited in claim 14, wherein:

the digital data streams are packetized elementary data streams that include compressed video and audio data streams according to the Moving Picture Expert Group (MPEG) standard.

20. A receiving device, comprising:

a transport data stream demultiplexer for demultiplexing a transport data stream into packetized elementary data streams and for extracting flags that identify a presentation time stamp for the purpose of initializing a system time clock counter;

a unit for correctly determining a sampling frequency of one of the packetized elementary data streams;

an output control unit for synchronizing data streams obtained from the packetized elementary data streams; and

a synchronization unit for synchronizing the system time clock counter according to the sampling frequency.

21. The receiving device as recited in claim 20, wherein:

the synchronization unit sets an increment of the system time clock counter, the increment being determined from a ratio between a program clock reference and a nominal sampling frequency.

22. The receiving device as recited in claim 20, wherein:

the increment is set to a constant value based on a nominal sampling frequency.

23. The receiving device as recited in claim 20, wherein:

the synchronization unit compares an instantaneous value of the presentation time stamp of the packetized elementary data stream used to determine the sampling frequency with an instantaneous count of the system time clock counter, and

the synchronization unit corrects an increment of the system time clock counter according to a comparison result.

24. The receiving device as recited in claim 20, wherein:

the unit for correctly determining the sampling frequency determines the sampling frequency from a selected packetized elementary data stream of different packetized elementary data streams, and

the output control unit synchronizes all packetized elementary data streams with the system time clock counter.

25. The receiving device as recited in claim 24, wherein:

the sampling frequency is determined from the elementary data stream having the greatest sampling frequency of any of the available packetized elementary data streams.

26. The receiving device as recited in claim 20, wherein:

the packetized elementary data streams are compressed video and audio data streams according to the Moving Picture Expert Group (MPEG) standard.