Patent ID: RE43093

Claim:
A digital TV receiver comprising: a receiving section for receiving a PSK (Phase Shift Key) modulation signal comprising a plurality of signal points disposed on specific phases of a given constellation in a signal space diagram; a demodulator for demodulating the received signal from said receiving section into a digital signal; an error correcting section for error correcting a demodulation signal from said demodulator; and an image expander for expanding an error-corrected signal from said error correcting section to a video signal, thereby outputting a video signal, wherein said demodulator demodulates the received signal as first and second PSK signals, said first PSK signal representing a first data stream to be reproduced, said first PSK signal comprising n-value signal points, said second PSK signal representing both said first data stream and a second data stream to be reproduced, said second PSK signal comprising m-value signal points, where m is an integer larger than n, wherein the m-value signal points of said second PSK signal are divisible into n groups of signal points which are distinguishable from one another in the signal space, and said demodulator distinguishes said n groups of signal points from one another as the n-value signal points of said first PSK signal by demodulating the received signal as said first PSK signal, and wherein high priority information is demodulated at least in said first data stream.