Detecting Human Pulse in P-SPICE Model Using Lock-In Amplifier

The goal of this project is to develop low noise pulse detection simulation models with the help of Lock-In analysis. This technique offers better result in extracting signal at extremely noisy environment. Two major noises that influence the detection of pulse signal are noise that comes from surrounding lights and noise from ripple voltage of power supply. The basic components of Lock-In analysis are modulation, multiplication and low pass filter. It uses the principle of amplitude modulation which is widely used in communication technique. Current-to-voltage converter (transimpedance) amplifier is applied in detecting signal from photodiode. The P-SPICE simulation models offer undergraduates to understand the concept of Lock-In analysis.