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01:24 Feb-09-2001
Terry Anson
Thanks for the help!

I appreciate all the advice! I have one more question. Is is possible to find a transducer that can sweep frequency? Maybe I should phrase it like this: If I buy a transducer that is rated at 200khz, will it will only send out a 200khz signal? Or will the voltage, current, and frequency of the pulse sent to the transducer determine this?


 
04:22 Feb-09-2001

Paul Meyer

R & D,
GE Inspection Technologies,
USA,
Joined Nov 1998
47
Re: Thanks for the help! Hi Terry,
Most ultrasound transducers respond to a range of frequencies. If you sweep the frequency of a constant amplitude input signal and monitor the output amplitude of the transducer you will difine the frequency response of the transducer. The bandwidth of the transducer (frequency range of the response) can be increased by changing the internal design of the device, but this sometimes reduces the maximum output amplitude.
Decide the frequency range that you need, and then work with your supplier to get as close to that as you can.
Paul


: I appreciate all the advice! I have one more question. Is is possible to find a transducer that can sweep frequency? Maybe I should phrase it like this: If I buy a transducer that is rated at 200khz, will it will only send out a 200khz signal? Or will the voltage, current, and frequency of the pulse sent to the transducer determine this?
.



 
07:58 Feb-09-2001
Hanspeter Loertscher
Re: Thanks for the help! All transducers have a certain bandwidth, i.e. the frequency is not sharply defined. The larger the bandwidth, the less sensitive the transducer. Resonant transducers, as we use them for air-coupled ultrasound, are highly resonant and have therefore a narrow bandwidth. Our solution to overcome the narrow bandwidth - the frequency of one specific transducer cannot cannot be swept - is an instrument, the SONDA 007CX, which is capable of driving transducers of different nominal frequencies, ranging from 50 kHz to 1 MHz. Each frequency is then precisely tuned to the resonant frequency of the transducer. We are preparing a paper and a presentation, which will show some very estonishing results using different frequencies for material testing.


 


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