| 摘要 |
A control unit (102) efficiently decodes burst signal transmissions in a TDMA-based telecommunication system (100) by decimating down the number of samples requiring processing during symbol detection. The control unit (102) includes a sampling receiver (304) that inputs burst signals from cable access units, converts them to a pair of baseband quadrature signals, I and Q. The sampling receiver (304) also includes an A/D converter (314) that samples the I and Q signals at preferably four times the symbol rate. A digital signal processor circuit (306) produces a timing error signal for substantially all of the samples. The digital processor circuit (306) also accumulates a timing error sum for each of the four samples. The processor circuit (306) selects the optimum sample as the sample between the samples having the largest positive and negative error sums. The processor circuit (306) also includes a pi /4-DQPSK differential detector that processes the optimum sample of each symbol for symbol detection. |
