Post by thread:[PICLIST] Understanding Ultrasonic Transducer Spec

Hello, I am planning to purchase a Panasonic Ultrasonic receiver and transmitter, but am having some trouble understanding the data sheet. Specifically, the transmitter has a sound pressure level (SPL) of 112dB re 2*10^-5 Pa (that is, 0dB=2*10-5 Pa). The receiver has a sensitivity of -45dB re 1V/Pa. Assuming the devices are ideal and I loss no signal strength between the transmitter and receiver is the following correct. 112dB = 10^(112/20)*(2*10^-5Pa) = 7.96 Pa So, the output of the receiver is: -45dB = 10^(-45/20)*1V/Pa = 0.0056 V/Pa 7.96 Pa * 0.0056 V/Pa = 0.044 V This just doesn't seem right as this would mean a receiver with a sensitivity of -90dB would have an output of 2.5*10-4V. More expensive receivers have a larger absolute value for their sensitivity so I must be looking at this incorrectly. Where am I going wrong? (Am I doing any of this right!) Regards, Donovan Parks -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email spam_OUTlistservTakeThisOuTmitvma.mit.edu with SET PICList DIGEST in the body