![](https://journeys.dartmouth.edu/gavinburns/files/2022/03/Amplified-Peak1-1024x507.png)
![](https://journeys.dartmouth.edu/gavinburns/files/2022/03/Pulse-Width-Modulator-1024x537.png)
![](https://journeys.dartmouth.edu/gavinburns/files/2022/03/Circuit-Board-768x1024.jpg)
![](https://journeys.dartmouth.edu/gavinburns/files/2022/03/Wienbridge-Circuit.png)
Problem
When a stethoscope picks up a heartbeat, it has a minute signal and is broken up into two smaller parts (a “Lub-Dub”). In order to properly monitor heart activity, heart monitors need to condition and amplify the signal into a proper readout. This is done through a wide range of means and in this project I was tasked with figuring out one of them.
Solutions
I began by first breaking down the problem into its individual parts. This starts with the amplification of the signal into a form that can be easily conditioned. Next, the conditioning the “Lub-Dub” into a single pulse. This single pulse will then be used to turn on a sawtooth wave generator which, with a sine wave and comparator, creates a pulse width signal that can be fed into a class Damplifier to produce the necessary audible tone.