Alpha Imaging Technology Corporation

Shu-Mei Li

Chingwo Ma

Chih-Chia Wang

Cen-Chieh Huang

Hsin-Chin Hsu

Szu-Chung Chang

Yi-Sheng Lin

An ACS unit of a Viterbi decoder and a method for calculating the bit error rate (BER) before Viterbi decoder are provided. The ACS unit includes a state calculator and a BER calculator. The state calculator calculates the state metric of a corresponding target state in the trellis diagram and selects one of two candidate source states as the selected source state of the target state. The state calculator also provides a selection signal indicating the selected source state. The BER calculator is coupled to the state calculator for providing the sum of the BER of the selected source state and the bit error count (BEC) of the transition from the selected source state to the target state as the BER of the target state.

ACS unit of a Viterbi decoder and method for calculating a bit error rate before a Viterbi decoder

A null detector and its corresponding method are provided. The null detector includes a power detector, a smoother, and an overlapper. The power detector outputs a power level signal according to the power level of a received signal. The smoother is coupled to the power detector for determining according to the power level signal whether the received signal is transmitting a null symbol, and then the smoother outputs a null detection signal at a first state value or a second state value indicating the result of the determination. The overlapper is coupled to the smoother for providing the duration and position of the null symbols transmitted by the received signal according to the null detection signal.

Null detector and method thereof

A time domain symbol timing synchronization circuit is disclosed, which comprises: an autocorrelation function calculator for calculating cyclic prefix autocorrelation functions and an offset time estimator for searching peak positions of cyclic prefix autocorrelation functions to indicate symbol boundary of received communication symbols. The offset time estimator compares a current peak position and a previous peak position. If (a) the difference of the positions is larger than a threshold and (b) the current peak is smaller than a reference average peak, the current peak is determined as false; the offset time estimator weeds out and replaces the current peak position by the previous peak position; and the current peak is not introduced in the reference average peak calculation.

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Taipei, Taiwan

Shu-Mei Li