APPARATUS FOR MAINTAINING SIGNAL LEVEL

PROBLEM TO BE SOLVED: To maintain a signal level in a digital segment when demodulating a received signal. SOLUTION: In a demodulation apparatus for demodulating a received signal that is transmitted from a remote source, the received signal contains an analog segment and a digital segment, the digital segment contains an OFDM waveform having at least a pair of fixed envelope carriers, and the total sum of the pair of fixed envelope carriers is orthogonal in phase with respect to an analog segment carrier. The apparatus for maintaining the signal level in the digital segment for use in the above demodulation apparatus is provided with a means for generating an error signal by measuring a fixed envelope signal output in the received frame in one frame or in frames of an integer multiple, and a scaling circuit means that uses the error signal to control the signal level. COPYRIGHT: (C)2005,JPO&NCIPI