Data clock generator, data clock generating method, and storage medium therefor

• US 6,671,343 B1
• Filed: 01/07/2000
• Issued: 12/30/2003
• Est. Priority Date: 01/14/1999
• Status: Expired due to Term

• Current Assignee: Yamaha Corporation
• Original Assignee: Yamaha Corporation
• Inventors: Ito, Tsugio
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): WILLIAMS, LAWRENCE B
• Application Number:
  US09/479,697
• Time in Patent Office: 1,453 Days
• Field of Search: 375/376, 710/58, 713/500-503, 386/96, 327/148-149, 369/50
• US Class Current: 375/376
• CPC Class Codes: H04J 3/0632 Synchronisation of packets and cells, e.g. transmission of voice via a packet network, circuit emulation service [CES] queuing arrangements in packet switching elements H04L49/90; synchronising systems for the synchronous transmission of a pulse code modulated video signal with one or more other pulse code modulated signals H04N7/56
• CPC Class Codes: H04J 3/0664 unidirectional timestamps
• CPC Class Codes: H04L 12/40091 Bus bridging LAN interconnection over a bridge based backbone H04L12/462; single bridge functionality H04L12/462

Abstract

A data clock generator, a data clock generating method and a storage medium therefor are provided, which make it possible to reduce burden on a PLL circuit and substantially reduce jitter in the generated data clock signal, as well as achieve a sufficiently wide lock range of the PLL circuit. Data packets are supplied, which include at least a plurality of data samples and time stamps which are smaller in number than the number of the plurality of data samples. Time samples are generated, respectively, for the data samples from the time stamps of the supplied data packets. A PLL circuit generates a data clock signal based on the time samples for the respective data samples.

Claims

1. A data clock generator comprising:

a supply device that supplies data packets including at least a plurality of data samples and time stamps which are smaller in number than a number of said plurality of data samples;

a time stamp-generating device that generates new time stamps for respective ones of said data samples, from said time stamps of said data packets supplied from said supply device; and

a PLL circuit that generates a data clock signal based on said new time stamps for the respective ones of said data samples generated by said new time stamp-generating device.

2. A data clock generator according to claim 1, wherein said data clock signal comprises a word clock for reading each of said data samples, and a bit clock for reading each bit data of each of said data samples.

3. A data clock generator comprising:

a supply device that supplies data packets, each of said data packets comprises a plurality of data samples and one time stamps;

a time stamp-generating device that generates new time stamps for respective ones of said data samples, from said time stamps of said data packets supplied from said supply device, each of said new time stamps being generated based on a difference between a time stamp of a present one of said data packets and a time stamp of an immediately preceding one of said data packets; and

a PLL circuit that generates a data clock signal based on said new time stamps for the respective ones of said data samples generated by said time stamp-generating device.

4. A data clock generator according to claim 3, wherein each of said time stamps is generated based on a quotient obtained by dividing said difference by the number of said plurality of data samples of each of said data packets.

5. A data clock generator according to claim 4, wherein each of said time stamps is generated by sequentially adding a zero-fold value of said quotient to a n−

1 fold value thereof to said time stamp of the immediately preceding one of said data packets.

6. A storage medium storing a program that is executable by a computer, the program comprising:

a supply module for supplying data packets including at least a plurality of data samples and time stamps which are smaller in number than a number of said plurality of data samples;

a time stamp-generating module for generating new time stamps for respective ones of said data samples, from said time stamps of said data packets supplied by said supply module; and

a data clock-generating module for causing a PLL circuit to generate a data clock signal based on said new time stamps for the respective ones of said data samples generated by said time stamp-generating module.

7. A storage medium according to claim 6, wherein said data clock signal comprises a word clock for reading each of said data samples, and a bit clock for reading each bit data of each of said data samples.

8. A data clock generating method comprising the steps of:

supplying data packets including at least a plurality of data samples and time stamps which are smaller in number than a number of said plurality of data samples;

generating time stamps for respective ones of said new data samples, from said time stamps of the supplied data packets; and

causing a PLL circuit to generate a data clock signal based on said new time stamps for the respective ones of the generated data samples.