Signal processing method and pulse wave signal processing method

A method of processing two continuous signals having an identical fundamental frequency, comprising the steps of:

• providing a first signal and a second signal as the two continuous signals;
• obtaining a first spectrum which is either one of a frequency spectrum or a frequency power spectrum of the first signal in a predetermined time period;
• obtaining a second spectrum which is either one of a frequency spectrum or a frequency power spectrum of the second signal in the predetermined time period;
• obtaining a first normalized value which corresponds a ratio of a difference between the first spectrum and the second spectrum and a sum of the first spectrum and the second spectrum at the fundamental frequency;
• obtaining a first ratio of an amplitude of a signal component of the first signal and an amplitude of a signal component of the second signal based on the first normalized value.