PULSE-WIDTH MODULATING CIRCUIT, PULSE-WIDTH MODULATING METHOD, PARAMETRIC SPEAKER, AND PULSE-WIDTH MODULATION CONTROL PROGRAM

摘要

PPROBLEM TO BE SOLVED: To provide a pulse-width modulating circuit etc., improving efficiency of a power amplifier. PSOLUTION: A ring counter unit 1a outputs a cycle count which varies between an initial value and a maximum value in a cycle shorter than the frequency of a PWM signal to be generated. Further, when the count value reaches the maximum value, a reset signal is outputted to a sampling data holding unit 1b and a PWM output unit 1d. The sampling data holding unit 1b, the reset signal is once inputted holds current modulated ultrasonic data as sampling data. A comparator 1c compares the sampling data with the cycle count, and outputs a coincidence signal to the PWM output unit 1d when their value match each other. The PWM output unit 1d generates the PWM signal having a pulse width corresponding to the generation interval between the reset signal and coincidence signal and outputs the PWM signal. PCOPYRIGHT: (C)2009,JPO&INPIT