| 摘要 |
A digital time division multiple access (TDMA) radio communications system employs a digital information source for providing digital information, a transmitter for transmitting encoded digital information in a radio-frequency (RF) signal to a receiver which demodulates the encoded symbols into digital information to be utilized by an output device. The receiver, synchronizes, compensates for frequency drift, samples and divides the samples into halfslots of samples. The halfslots are subdivided into subslots numbered from 1 to N, where N represents the last received subslot. Subslots 1 and N are demodulated into digital information in a forward and reverse direction, respectively with metrics calculated. If the metrics indicate a signal with a larger signal-to-noise ratio from subslot N, subslot N-1 is demodulated in a reverse sense with another reverse metric calculated, and vice versa. This process of extending demodulation in the direction of greater signal strength is repeated until all subslots in the slot have been demodulated. A second embodiment passes through all subslots in a forward and reverse direction calculating subslot metrics. The subslot metrics are summed into a halfslot metrics. The best halfslot metric indicates the sense of demodulation of each subslot. The digital information is then dumped in the proper order and sense to an output device which utilizes the digital information resulting in increased performance during fade periods.
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