| 摘要 |
A digital modulator for modulating a stream of incoming data bits in which at least each one of the bits corresponds to a symbol. The modulator includes storage for each incoming set of symbol bits, where there is at least one bit in each set, of "n" successive symbols where "n" is a positive integer with a value greater than or equal to 1, with the oldest stored set being discarded upon the arrival and storage of a next set of symbol bits. Memory stores sample values corresponding to a modulated symbol impulse response for each of a predetermined number of symbols wherein the modulated symbol impulse responses each extend over "n" symbol periods. Sample values over one symbol period are retrieved from the memory for overlapping portions of each of the modulated symbol impulse responses stored in the storage. An adder sums the sample values which correspond to each other in time for each of the modulated symbol impulse responses corresponding to the received symbols. A converter converts summed digital sample values to an analog signal for subsequent transmission.
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