http://forum.allaboutcircuits.com/threads/doppler-ultrasonic-transducer.54006/
Does any body know the answer to his Question?

 

The link to the information in that thread is dead which isn't surprising given that it is 5 years old.

 

The link to the information in that thread is dead which isn't surprising given that it is 5 years old.

Any idea about how can i get a circuit for fetal doppler monitor? Or how can I get the details of the above circuit?

 

i can see several options:
- follow the link, (which does not go anywhere anymore)
- study that circuit design
- make your own design
- use search to find same or other designs
- hire someone to do design for you

 

I found this (possibly) related project:
https://web.archive.org/web/20121023010026/http://blockyourid.com/~gbpprorg/mil/ultra/index.html
This circuit operates at 40 KHz which is not appropriate for a fetal heart monitor.


Look here for some basics on fetal heart monitors:
https://en.wikipedia.org/wiki/Doppler_fetal_monitor

A couple of comments. Note that the transducer operating frequency is stated to be from 2 to 3 MHz. I expect that a lot of voltage gain in the receiver is needed -- something like 80 dB.

 

Popular Electronics August 1975 has a lengthy How-To on page 60. It uses 2 MHz:
https://archive.org/details/Poptronics197508ListenToYourHeartWithDopplerUltrasound