A signal processing circuit includes: a first operation circuit for receiving a phase component of an input signal, and generating an adjusted phase component and at least one weighting factor according to the phase component of the input signal; a second operation circuit, coupled to the first operation circuit, for receiving the adjusted phase component and converting the adjusted phase component into a frequency component corresponding to the adjusted phase component; a third operation circuit, coupled to the first operation circuit, for receiving an amplitude component of the input signal, and adjusting the amplitude component according to the at least one weighting factor to generate an adjusted amplitude component; and a fourth operation circuit, coupled to the second operation circuit and the third operation circuit, for generating an output signal according to the frequency component and the adjusted amplitude component.