Noise propagation measurement using a signal detection technique
Yasushi Ishii, Juichi Igarashi, Ichiro Yamada, Yukinobu Miki · The Journal of the Acoustical Society of America · 1978
A new technique to measure the ground to ground noise propagation was developed. The test sound of a band limited noise is emitted from a speaker intermittently, a several seconds burst of the noise followed by a pause of the same period. At the receiving spot, the sound intensity is integrated alternatively by two digital counters. One counter integrates the intensity of the test sound plus the background noise at that spot in the period for which the test sound is present. The other integrates the intensity of the background noise in the absent period of test sound. Synchronization of the devices at the source and receiving spots is kept by wireless means such as transceivers. After the completion of a predetermined number of integrations, the difference of the accumulated numbers in the two counters is read, which gives the intensity of the test sound at the receiving spot. Experiments using a 7-W speaker showed that the noise attenuations of the distance of 170 m can be measured with the statistical error less than 0.5 dB.