Stiff osc source on the reflective properties of an ultrasonic transducer

I have an ultrasonic transducer that I am driving in pulsed mode from a fai rly stiff opamp source. The result being that when V=GND after transmitti ng the pulse there is almost no trace of ringing on the transducers Tx circ uit as the opamp feedback suppresses it.

The question becomes whether the face of the transducer will still efficien tly reflect other ultrasound pulse impinging on it, or whether it acts as s ome kind of active damper?

Reply to
Dirk Bruere at NeoPax
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airly stiff opamp source. The result being that when V=GND after transmit ting the pulse there is almost no trace of ringing on the transducers Tx ci rcuit as the opamp feedback suppresses it.

ently reflect other ultrasound pulse impinging on it, or whether it acts as some kind of active damper?

Additional info - the frequencies of interest are around 150kHz and the opa mp response is in the tens of MHz

Reply to
Dirk Bruere at NeoPax

On a sunny day (Fri, 15 Aug 2014 02:07:34 -0700 (PDT)) it happened Dirk Bruere at NeoPax wrote in :

It will reflect.

Reply to
Jan Panteltje

It would seem so, but I was also wondering about the transducer actively altering the phase of the reflected wave etc because in the real world the response is not infinitely fast.

With a suitable delay it could resonate in anti-phase and cancel the incoming wave, but given the low frequencies it seems unlikely. Anyway, I will know for sure next week when I breadboard it.

Dirk

Reply to
Dirk Bruere at NeoPax

At first sight, holding still the surface of the transducer by active feedback makes it appear hard and rigid, so you'd expect full reflection. The actual dynamics may not be that ideal however. You'd have to test to make sure.

Making an efficient active damper is likely much harder than making a good reflector. (Or you may find a good job at the navy...)

Jeroen Belleman

Reply to
Jeroen Belleman

On a sunny day (Fri, 15 Aug 2014 05:21:43 -0700 (PDT)) it happened Dirk Bruere at NeoPax wrote in :

Even with in phase there is only a small part of the transducer that moves, the housing etc will relect.

Reply to
Jan Panteltje

Fortunately I want a good reflecting surface

Dirk

Reply to
Dirk Bruere at NeoPax

I doubt that the acoustic reflectance of the transducer will measurably depend on the electrical impedance applied to its leads. The coupling from a solid surface to air is tiny.

But try it!

--
John Larkin         Highland Technology, Inc 

jlarkin att highlandtechnology dott com 
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Reply to
John Larkin

At one time, while playing with a piezo tweeter, I was surprised to see how sensitive the tweeter current was to the distance of reflective surfaces nearby. It's too long ago to remember any figures. I just remember it was pretty obvious. OK, not quite the same thing. Never mind.

Jeroen Belleman

Reply to
jeroen Belleman

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