Software radio architectures - part 2

Abstract

Radio modulation simulation programs using Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK), Quadrature Amplitude Modulation (QAM), and Minimum Shift Keying (MSK) were developed in this Research Project. All programs were written using Matlab 6.5. The success of these programs is attributed to embedding them in a Linear Predictive Speech Coder (LPC10) which only requires 11 parameters (10 coefficients and pitch delay) to be modulated as opposed to a whole block of quantized voice samples. Coherent demodulation is effectively achieved for BPSK by employing a squaring loop which locks onto to a signal that is twice that of the carrier frequency and scales it down. The program works effectively to recover carrier frequencies within an appropriate range. The squaring loop program implements the vital components of filtering, squaring, phase detection, and numerically controlled oscillation in Matlab code. Also included in this dissertation is an introduction to the EZ-KIT Lite Digital Signal Processor (DSP) package developed by Analog Instruments. An investigation of this DSP environment takes steps towards realizing a software radio which executes in real time.