Demodulating device, broadcasting system, and semiconductor device

Abstract

A demodulating device capable of high-efficiency, high-accuracy phase noise correction control and improved in quality and reliability. A digital signal generating portion synchronously detects a modulated input signal and subjects the signal to A/D conversion to generate digital signals corresponding to phase axes. A timing recovery portion extracts symbol timing of the digital signals to recover timing. A carrier recovery portion sets a gain for a phase difference between the timing-recovered digital signals in accordance with a phase noise correction signal, and rotates symbols in a direction to suppress phase noise in accordance with an oscillation signal generated based on the gain, to recover carrier. A phase noise correction portion outputs the phase noise correction signal which takes a value equal to an increase of the phase difference when the phase difference has increased on the positive side, and which takes a value obtained by multiplying an increase of the phase difference by '−1' when the phase difference has increased on the negative side.