Patent ID: 7884667

Claim:
A pulse area modulation method for amplifying an input signal, whose values are f(t 1 ), f(t 2 ), . . . f(t 2 ) at times t 1 , t 2 , . . . t n , respectively, at which the input signal is sampled for a pulse modulation, the values of the input signal having a characteristic that if the input signal were modulated by the pulse width modulation (PWM), the pulse width modulated signal would have a waveform with a height of 1 and with widths of x 1 , x 2 , . . . x n , wherein x k is proportional to f(t k ) (1<=k<=n), wherein in case the values of the input signal having a minimum value of m and a maximum value of M are partitioned by threshold values Th 1 , Th 2 , . . . Th n−1 , while an inequality: m<Th 1 <Th 2 <. . . <Th n— <M is satisfied, if the value of the input signal at tk satisfies an inequality: f(t k )<=Th 1 , the modulated input signal by the pulse area modulation method has a waveform with a height of H 1 and with a width of x 1 *H 1 , if the value of the input signal at tk satisfies an inequality: Th q−1 <f(t k )<=Th q , the modulated input signal by the pulse area modulation method has a waveform with a height of 1/H q and with a width of x q *H q , and if the value of the input signal at t k satisfies an inequality: f(t k )>Th n−1 , the modulated input signal by the pulse area modulation method has a waveform with a height of 1/H n and with a width of x n *H n , wherein 1<=H n <H n−1 < . . . <H 1 and 2<=q<=n−1.