ULTRASONIC-WAVE TRANSMISSION DEVICE, ULTRASONIC-WAVE RECEIVER, ULTRASONIC-WAVE TRANSMISSION METHOD, ULTRASONIC-WAVE RECEPTION METHOD, PROPAGATION TIME MEASUREMENT SYSTEM FOR TEMPERATURE MEASUREMENT, AND PROPAGATION TIME MEASUREMENT METHOD FOR TEMPERATURE MEASUREMENT

摘要

PROBLEM TO BE SOLVED: To precisely separate plural ultrasonic signals simultaneously or substantially simultaneously transmitted to measure the temperature in a measurement target space using a pseudo noise code with a high autocorrelation.SOLUTION: In N encoding periods corresponding to a code (+1 or -1) in a series of pseudo noise codes of a code length N (N: integer) allocated to each sensor units, a sensor unit SU1 transmits an ultrasonic signal which is a pulse signal modulated using a code in the series of the pseudo noise codes. The sensor unit SU1 demodulates the ultrasonic signal which is received over N encoding periods using a code in the series of pseudo noise codes corresponding to the other plural sensor unit SU5 and SU6 to calculate a received signal envelope for each of the other plural sensor units.