Accumulator based PCR restamping

Current DTV systems like DVB or ATSC are based on MPEG-2 transport streams. A single transport stream (TS) combines several programs while each program is related to an independent time base. The elementary stream packets that make up a single program share a common time base. These time bases represent numerical samples of the original system clock frequency and are called program clock reference (PCR). MPEG-2 defines further time stamps associated with the PCR to ensure the synchronization of the selected program at the receiver. During the transfer process a TS is converted by different transmission components. Therefore a restamping process accomplishes the required PCR correction. This paper presents a new fully digitized PCR restamping approach without the need of an additional local clock oscillator. By applying this new method a simplified printed circuit board design of transmission adapters and multiplexers can be achieved. To demonstrate the proposed technique, measurement results based on this restamping algorithm implemented in an A-VSB transmission adapter are presented.