Knock is produced by transducer (alone pulse).
Signal after knock, received by transducer,
processed by program (Fast Fourier Transform, FFT).
Hence you can draw conclusion about fluid level.

Yes, I am following the same procedure, the only problem is Knock is produced by the transducer, but signal after knock is no received by the transducer...If I had received the signal after knock, we wouldn't be having this discussion right now..:-D

 

Yes, I am following the same procedure, the only problem is Knock is produced by the transducer, but signal after knock is no received by the transducer...If I had received the signal after knock, we wouldn't be having this discussion right now..:-D

Your setup is good, but you should use low frequency, wideband, non-resonant transducer.
For experiment you can try electrodynamic loudspeaker as transducer:

 

Your setup is good, but you should use low frequency, wideband, non-resonant transducer.
For experiment you can try electrodynamic loudspeaker as transducer:
View attachment 172429

Hi Danko,
This setup is not feasible for my application.
But anyways thanks for the suggestion.

 

Hi EricGibbs,

Did you find any solution for detecting echo through 1 MHz piezo...?

 

Hi EricGibbs,
Did you find any solution for detecting echo through 1 MHz piezo...?

Hi,
The way I recommended would be to increase the drive to the piezo, either by a tuned step up transformer in the MOSFET driver or increase the drive voltage, which would mean a higher voltage rated MOSFET.
My choice would be a transformer and time swept gain and TXP suppression.

E

 

Hi,
The way I recommended would be to increase the drive to the piezo, either by a tuned step up transformer in the MOSFET driver or increase the drive voltage, which would mean a higher voltage rated MOSFET.
My choice would be a transformer and time swept gain and TXP suppression.

E

Hi EricGibbs,

Based on your suggestion, I have done some changes in the TX circuit. I am sharing the .asc file, please check and provide your inputs in it.

 

hi,
Look at the Transient response and AC Analysis of your circuit.
The power in the PZ is much too low and the resonant frequency is approx 400MHz.
This is due to the incorrect design of the transformer.

Also you have changed the resistance of the piezo from 2R to 25R, this will give you incorrect results in simulation.
E

 

hi,
Look at the Transient response and AC Analysis of your circuit.
The power in the PZ is much too low and the resonant frequency is approx 400MHz.
This is due to the incorrect design of the transformer.

Also you have changed the resistance of the piezo from 2R to 25R, this will give you incorrect results in simulation.
E

Hi,

Can you update the design file and send it to me, accordingly, I guess I am not quite yet familiar with designing transformer ;-)

 

hi,
This is the way that I would do.
E

 

hi,
This is the way that I would do.
E

Hi Eric,
I have made the similar changes in the circuit, but my output is different..please check and let me know if I missed something.

 

hi,
You have the L2 and L3 inductors crossed over.
Also the 2N7002 drive pulse is 0.1us and 0.9us
E

 

hi,
You have the L2 and L3 inductors crossed over.
Also the 2N7002 drive pulse is 0.1us and 0.9us
E

Yes, Got it.
Also have you taken a look at the receiver part of the circuit, It is giving quite messy output.

 

Please define 'Messy output', post an image.

 

Please define 'Messy output', post an image.

Please Find the attached image and .asc file.

 

hi,
You have the supplies +v and v+ , they must be the same.!
Also why have you changed the simulated Echo source.?
E

 

hi,
You have the supplies +v and v+ , they must be the same.!
Also why have you changed the simulated Echo source.?
E

Yes, Thanks for pointing out the v+ and +v confusion.
I have changed the simulated echo because it is similar to what I am observing through oscilloscope....

 

hi,
Try this latest version.
Note: on the real version you may have to add some damping on the pz line to 0V, its shown as R11 on this circuit.

E

 

Hi Danko,
This setup is not feasible for my application.
But anyways thanks for the suggestion.

You are so right, this setup is for experiment only.
For everyday work Hand-held Exciter Type 5961
and miniature Force Transducer Type 8203
are much easier to handle:

http://www.music.mcgill.ca/caml/lib/exe/fetch.php?media=equipment:bo0409.pdf
http://www.bruel.hu/pdf/bf0236.pdf

 

hi,
Try this latest version.
Note: on the real version you may have to add some damping on the pz line to 0V, its shown as R11 on this circuit.

E

Hi Eric,
Why don't we use sine wave as simulated echo signal, rather than using a pulse signal, because the nature of the echo that I am seeing is very close to sine wave signal rather than a pulse signal..?

 

You are so right, this setup is for experiment only.
For everyday work Hand-held Exciter Type 5961
and miniature Force Transducer Type 8203
are much easier to handle:
View attachment 172650
http://www.music.mcgill.ca/caml/lib/exe/fetch.php?media=equipment:bo0409.pdf
http://www.bruel.hu/pdf/bf0236.pdf

Thanks Danko,
I will review the documents and let you know about it.