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'[PICLIST] Understanding Ultrasonic Transducer Spec'
2002\03\21@233834
by
Donovan Parks
|
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
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