Fundamentals

Phase Locked Loop is an important circuit found in various communication devices, and here studied in a set up to synchronize input and local carrier signals for coherent demodulation of AM signals. PLL consists of a phase detector, a loop filter, and a voltage controlled oscillator. The phase detector and loop filter combined produces an error signal which amplitude is linearly related to the phase difference of input and local carrier signals. The voltage-controlled oscillator adjusts appropriately to tune both signals as desired.

Artificial neural network can classify groups. Multi-layer perceptron (back propagation) is suitable and widely used to solve complex classification problems. The aim of the project was to "illustrate the learning behavior of back-propagation neural network for pattern classification". In particular, the task was to write a MATLAB program to implement the back propagation algorithm to classify two classes defined by the following conditional probability density functions.