ORTHOGONAL MODULATION CIRCUIT

摘要

PURPOSE:To reduce an image signal component causing interference to other channel by forming a circuit with a waveform shaping means, an orthogonal modulation means, and an orthogonal phase error compensation means compensating an orthogonal phase error of a channel output data of the waveform shaping means. CONSTITUTION:A waveform shaping means 1 applies band limit to a channel data inputted from an input terminal 4, offsets a frequency corresponding to each of plural channels and outputs a channel data. An orthogonal modulation means 2 fetches a channel data outputted from the waveform shaping means 1 to implement phase modulation and generates and outputs a modulation signal. An orthogonal phase error compensation means 3 extracts an image signal component in the modulation signal outputted from the orthogonal modulation means 2 and detects an amplitude of the image signal component to detect an orthogonal phase error of the orthogonal modulation means 2. Then the orthogonal phase error of the channel output data of the waveform shaping means 1 is compensated by the detection signal.