Patent ID: 7539258
Filing Date: 2009-05-26
Classification: G10L,H04N

Abstract:
1. An audio data sync format detecting circuit comprising: a data register into which audio data is written in sequential units per a predetermined period; a first sync format register which stores a first sample of sync format data which indicates a format of audio data, the sync format data including a plurality of subsequent samples in addition to the first sample; a second sync format register which stores the plurality of subsequent samples of the sync format data, the plurality of subsequent samples being stored one subsequent sample at a time; a first comparator that compares the first sample stored in the first sync format register with data written to the data register, and outputs a sync start signal when the first sample matches the data written to the data register; a second comparator that compares the subsequent sample stored in the second sync format register with data written to the data register, and outputs a hit signal when any one of the subsequent samples matches the data written to the data register; and a control circuit that writes a first subsequent sample to the second sync format register in response to the sync start signal, updates the second sync format register with subsequent samples each time the hit signal is output, and outputs a format match signal when the hit signal is output a predetermined number of consecutive times, wherein the first sync format register retains the first sample of sync format data and the first comparator continues to compare the retained first sample with data written into the data register to potentially output a sync start signal to restart sync detection by the sync format detecting circuit, independently of whether one or more hit signals have been output by the second comparator since a previous sync start signal.