ADD-COMPARE-SELECT CIRCUIT FOR VITERBI DECODER

There is provided a viterbi decoder for decoding convolutional data. The convolutional data includes punctured data and non punctured data. The decoder includes a branch metric unit for calculating branch metrics of the received convolutional data. An add-compare-select unit selects current and next path selection information and calculates a current state metric and a next state metric of the punctured data, from the branch metrics and a previous state metric. A traceback unit traces the current and the next path selection information selected in the add-compare-select unit to find a maximum likelihood path from which the convolutional data was received, and outputs decoded data. A controller generates a plurality of decoding control signals to the branch metric unit, the add-compare-select unit, and the traceback unit.