Patent ID: 6087960
Filing Date: 2000-07-11
Classification: G01H,G01V

Abstract:
An accident sound detection circuit for detecting an accident sound by using a sound signal produced by an environmental sound detection unit located in the vicinity of a road, the accident sound detection circuit comprising:an analog-to-digital (A/D) converter for converting a sound signal from an environmental sound detection unit into a digital sound signal;differential calculation means for generating an acquired differential signal from an output signal of said A/D converter;a reference differential value generating circuit for generating a reference differential value;a first comparator circuit for comparing the acquired differential signal to the reference differential value, detecting an accident sound from a comparison of the acquired differential signal to the reference differential value, and generating an accident sound detection signal in response to detecting an accident sound; andauto-correlation calculation means for auto-correlation of the digital sound signal received from the A/D converter when an accident sound detection signal is input;a correlation reference value generating circuit for setting an auto-correlation reference value of a sound signal for discriminating among different kinds of accident sounds; anda second comparator circuit for comparing the auto-correlation reference value and the auto-correlation of the digital sound signal and for generating a final accident sound detection signal in response to the comparison of auto-correlation of the digital sound signal and the reference value.