Far be it for me to rain on your parade, but if you're interested in seeing what the state of the art is, I recommend a little excursion down patent lane.
You'll easily find modern patents with noise cancelling (for example, lung sounds) along with other DSP algorithms.
As a for instance, check out US Patent 10,765,399 issued to Johns Hopkins.
On Mon, Dec 18, 2023 at 5:33?PM Jerry Lee Marcel <jerryleemarcel@...> wrote:
Transducers used in body exploration require a certain amount of
filtering and dynamic processing. Amplification in itself is
generally not too difficult, but the frequency response must be
tailoed to eliminate a smuch as possible parasitics, in particular
very low frequency due to moves and 50/60Hz due to mains voltage.
Some kind of dynamic processing is necessary in order to avoid
large surges that could be damaging for the person who listens in
case the transducer is hit.
Electret capsules of the omni type have a very good response down
to a few Hertz.
The actual circuits are not terrily complicated; what makes the
equipment so expensive is the safety implements and the ensuing
certifications. You don't want your electronic stethoscope turning
into an electric chair.
Le 18/12/2023 ¨¤ 22:26, Paralogic a
¨¦crit?:
Hi
everyone,
I
am a cardiologist. For a fun activity, I am working on my own
electronic sthethoscope design.?
Heart
sounds are low frequency and low intense sounds. (About 20 to
1200 Hz). Are listened to by touching the skin surface, that
makes them susceptible to motion artifacts.
I
am looking forward to the suggestions of the audio experts in
this group on the following topics:
Which
mic capsule, amplifier circuit and ext. should I prefer?
Is
it better to make a diy circuit or are there commercial ones
to handle my needs?
I
guess that mic sensitivity and frequency range is important,
are there ways to electronically modify mic sensitivity??
Which
solutions can be made about motion artifacts?
And
what about noise cancelling?
Thank you in advance?
