Signal processing circuit and method thereof

A signal processing circuit, adjusting a received radio frequency (RF) signal according to a gain, and generating a digital signal accordingly, the signal processing circuit comprising:

• a signal analysis circuit, for analyzing the digital signal to generate the gain, adjusting the RF signal with the gain accordingly, and determining whether the received RF signal is a target signal while simultaneously generating a reference value according to the digital signal;
• and
• a baseband circuit, coupled to the signal analysis circuit, for performing a carrier frequency offset (CFO) compensation to the digital signal according to the reference value;
• wherein the gain is reduced when the digital signal is in saturation;
• wherein, the reference value is a complex value or a phase calculated according to the complex value generated by a summation of the product of the digital signal and its complex conjugate over the period of the digital signal.