A multigroup STC system

An integrated MPEG2 system time clock unit able to recover and track the time base of up to four MPEG2 transport streams is presented. The described architecture allows generation of a time base for a dual/quad MPEG video/audio decoder system. The ability to receive 27 MHz clock from various sources and recover and track the encoder clock by using hardware/software methods results in greater flexibility and reduction of hardware cost. The proposed algorithm of a digital control system for 27 MHz clock recovery is shown to have a good performance and low computational complexity.