Signal receiving system, band detection method for multi-carrier signal and demodulating apparatus thereof

A demodulating apparatus for a multi-carrier signal, comprising:

• a frequency domain signal converter, receiving an input signal and converting the input signal to a plurality of carriers of a frequency domain;
• a calibration information calculator, coupled to the frequency domain signal converter and receiving the carriers, wherein the calibration information calculator is configured to perform operations as follows:
• defining a scan area range according to a full band range of the carriers;
• obtaining a reference symbol corresponding to each of the symbols of each of the carriers in the scan area range according to a time offset value and a frequency offset value;
• performing an operation according to the symbols of each of the carriers and the respectively corresponding reference symbols to generate calibration information corresponding to a carrier frequency of each of the carriers;
• and
• a band detector, coupled to the calibration information calculator and tuning the full band range of the carriers according to the calibration information corresponding to the carriers,
• wherein the time offset value and the frequency offset value are set according to pilot signals of the carriers.