Signal processing apparatus and associated method

A signal processing apparatus, comprising:

• an initial detecting module, for determining an initial carrier frequency offset of an input signal according to a spectrum of the input signal;
• a mixer, for adjusting the input signal according to the initial carrier frequency offset to generate a frequency-compensated signal;
• a symbol rate detecting module, for determining a symbol rate of the input signal;
• a judging module, for performing a phase recovery on the frequency-compensated signal, and judges whether the initial carrier frequency offset is correct as a judgement result according to whether the phase recovery renders a phase locking;
• and
• a correcting module, coupled to the mixer, for selectively determining a corrected carrier frequency offset according to the symbol rate and the spectrum and providing the corrected carrier frequency offset to the mixer based on the judgment result.