| 摘要 |
PURPOSE: A digital modulation device and a method of digital TV transmitter are provided to directly modulate the MPEG-II transfer stream input to the transmitter into digital signals. CONSTITUTION: A digital modulation device of digital TV transmitter comprises a channel coder(301), a phase shifter(303), a synchronous processor(304), a carrier frequency phase synchronous loop(311), a frequency elevator(310), a sine operator(307), a cosine operator(306), first/second multipliers(305,308), an adder(309) and a D/A converter(312). The channel coder(301) codes an MPEG-II transfer stream. The phase shifter(303) generates I and Q signals by shifting the signals output from the coder(301) by a right angle. The synchronous processor(304) matches the phase synchronous of the I and Q signals. The phase synchronous loop(311) generates a carrier frequency by matching the phase synchronous of the carrier frequency.
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