ALARM

PROBLEM TO BE SOLVED: To surely output a sweep sound including a frequency obtaining maximum sound pressure. SOLUTION: A PWM processing part 54 generates and outputs a PWM pulse string having a constant duty ratio and a frequency linearly changing corresponding to lapse of time in a sweep frequency range including an initially set maximum sound pressure frequency fp1, and outputs a sweep sound from a speaker 46 via a low pass filter 42 and an amplifier 44. A measuring processing part 56 outputs the sweep sound from the speaker 46 by the PWM processing part 54 to measure sound pressure when a sound pressure measuring mode is set. An EEPROM 32 receives and stores the measured maximum sound pressure frequency fp2 acquired by the sound measurement. A frequency range correcting part 58 shifts an initially set position of the maximum sound pressure frequency fp1 in the sweep frequency range to the stored measured maximum sound pressure frequency fp2, and corrects the sweep frequency range. COPYRIGHT: (C)2010,JPO&INPIT