US 7,003,796 B1 · Method and apparatus for recovering data stream clock

Abstract

A home network architecture has an internal digital network interconnecting devices in the home. Entertainment services are introduced into the network through network interface units that are coupled to an external network and to the internal network. The network interface units perform the necessary interfacing between the external and internal networks and perform MPEG clock recovery from an MPEG video data stream. To prevent jitter when the MPEG data stream is transmitted over the internal network to set-top electronics, the recovered MPEG clock is locked by the network interface unit to the internal network clock and then transmitted over the internal network. The set-top electronics then recovers the MPEG clock from the locked MPEG clock transmitted over the internal network. The video data may then be generated using the recovered MPEG clock and displayed on a television, for example.

Claims13

Dependent claims

A method for distributing an MPEG clock over an internal network by recovering an MPEG clock from a stream of data received from an external network, comprising the steps of:

recovering an MPEG related clock from a stream of MPEG data received from the external network at a network interface unit;
selecting a program from the stream using an MPEG transport chip located within the network interface unit;
direct locking a local clock to the recovered MPEG related clock to provide an internal clock for the internal network which is locked to said recovered MPEG related clock;
transmitting the MPEG data from the network interface unit over the internal network according to the internal clock;
synthesizing the MPEG clock at set-top electronics coupled to the internal network from the MPEG data transmitted over the internal network according to the internal clock.

2 more elements

An arrangement for recovering an MPEG clock from a stream of MPEG data comprising:

a network interface unit that receives an MPEG data stream from an external network and transmits MPEG data to predefined set-top electronics;
the network interface unit having an MPEG clock recovery circuit for recovering the MPEG clock from the stream of MPEG data, an MPEG transport chip for selecting a program from the stream, and a first frequency synthesizer for direct locking an internal clock to the recovered MPEG clock;
said predefined set-top electronics having a second frequency synthesizer for synthesizing the MPEG clock from MPEG data clocked over the internal network according to the internal clock;
and
wherein the internal network comprises a plurality of set-top electronics, including said predefined set-top electronics, and a switching hub connecting said network interface unit to at least said predefined set-top electronics having said second frequency synthesizer;
said switching hub including direct synchronous connections for connecting said network interface unit to said predefined set-top electronics for transmission of said MPEG data from said network interface unit to said predefined set-top electronics for synthesizing said MPEG clock at said predefined set-top electronics;
thereby avoiding delays in accessing the network and upsetting of clock reference timing included in said MPEG data stream.

4 more elements

Dependencies are inferred from the claim text.

Method and apparatus for recovering data stream clock

Life of this patent

Method and apparatus for recovering data stream clock

Life of this patent

Abstract

Claims13