Service clock recovery for variable bit rate services

A transmitter for transmitting data from a variable bit rate data source when the data generated at said source is at a rate not proportional to a service clock, comprising

• means for generating a service clock,
• a buffer for storing said variable bit rate data from said source,
• means for generating timing cells at a rate proportional to said service clock, and
• means for embedding said timing cells and said data stored in said buffer into a bit stream for transmission to a receiver.

A transmitter for transmitting data from a variable bit rate data source when the data generated at said source is at a rate not proportional to a service clock, comprising

• means for generating a service clock,
• a buffer for storing said variable bit rate data from said source,
• means for generating timing cells at a rate proportional to said service clock,
• means for tagging sad timing cells with numbers to reflect the order in which said timing cells are transmitted, and
• means for embedding said timing cells and said data stored in said buffer into a bit stream for transmission to a receiver.

A receiver for recovering at a destination location the service clock of an originating location variable bit rate source from timing cells received, comprising

• a buffer for storing variable bit rate data transmitted by said variable bit rate source to said receiver via a network,
• means for indicating the arrival at said receiver of numbered timing cells generated at said source at a rate proportional to said service clock and transmitted via said network,
• means responsive to timing cell numbers to correct for missing timing cells, and
• a phase locked loop responsive to said timing cells for reading said data out of said buffer at a rate which is proportional to said service clock.