Transmission/recepcion same via

[Augusto]

i need help, currently im working in a pulser for transducers and ultrasonic signal, i have two circuits, for TRANSMITTER and for RECEIVER, my problem is that i am using a transducer that is able to send and receive the signal by the same via, how can measure the received signal? if in the same wire i have the signal that i send and the signal that I receive.

 

[cowboybob]

Welcome, Augusto!

Is this a test bed? Is it an analog or digital signal?

Can you provide a block diagram of your system?

It's not immediately clear how your system is configured.

If your sent and recieved signals are using the same wire(s), there is a presumed delay between the two, correct?

 

[ericgibbs]

Hi,
As Bob suggests a diagram would be helpful for discussion.

One way is to use TGC in the receiver, Timed Gain Control, also clamp the RX amp input signal to low level.
E

 

[Augusto]

I think that is a test bed (im not sure about the exact definition), i use this circuit to send ultrasonic signals in a medium.
The first diagram is the original idea, but i going to use only a transducer for transmission and receive (this is possible, there are some devices that do that). I attach an image for transmission and receiver too. this is for

 

[ericgibbs]

hi,
What frequency is the system, looks about 1MHz, also what power output and required detection range through what medium.?

 

[cowboybob]

Thank you, Augusto.

Timing and ringing (with resulting residual biasing) is a bit of an issue here.

What is this being used for?

 

[Augusto]

the phase velocity is 1Mhz and group velocity is 10Hz (is a tone burst), this is amplified to 15 volts by the transmissor, and sent to the transducer similar to the image

the transducer receives the signal in the range of milliVolts, is why the receiver has a amplifier stage. This is used to determine in materials if there are defects, as the image above if there are some defect the signal arrives faster

 

[cowboybob]

Still don't know the density of the UUT, although not so sure that it matters in this case.

The uc can surely handle the timing issues (with some reprogramming) of switching between the xmit and recv functions of a single transducer within the timing you've provided.

What I'm concerned with is the mechanical ability of the transducer to shed any residual ringing, within picosecond time frames, before it's asked to successfully produce a reliable return signal.

<EDIT> As an afterthought, it strikes me that the developer of the sytem would have used a single tranducer if it had been reasonable to do so. Again, the timing issues are significant.

 

[ericgibbs]

hi Augusto,

Ultrasonic flaw/crack detection using HF ultrasonics is already a well developed procedure, is there anything novel in your method.?
E

 

[cowboybob]

My thanks to eric.

From his attachment:

It's the "ring down" that I was refering to.

 

[Augusto]

Well, Ultrasonic flaw/crack detection using HF ultrasonic is not new, but im going to incorporate this technique in a XYZ robot axis to control the desired force, currently I am using the device that I show you below (pulser 5800), It has 2 operating modes, R and R/T (receiver and receiver/transmissor) the transducer that i use only has 1 input and is used in the two modes, if i had 2 of them is posible to use one for receiver and other for transmissor, but the force control that I am developing requires R/T mode