Abstract

Multirate Digital Signal Processing (DSP) theory and technique are essential to digital communications, sonar and radar systems, speech and image processing, as well as many other applications. A computer aided design system that can significantly simplify the design and optimization of multirate signal processing structures has been presented in this thesis. The thesis starts with the introduction of fundamentals of multirate digital signal processing. It is followed by the introduction of the principle and technique of Multirate Signal Flow Graph (MSFG). A number of MSFG identities and transformations are also given in the thesis. The computer aided design system that has been presented in this thesis is based on the MSFG representation and transformations. With this system, instead of manual manipulation of MSFGs, the transformations and optimization of MSFGs that represent multirate signal processing systems can be performed in an automatic or interactive manner. With this system, one can represent a multirate system in the form of a MSFG and then optimizes it by performing a series of MSFG transformations interactively. The system has the capability of calculating the output response at any CELL in the MSFG. This feature can be used to verify the correctness of the derived network. To perform the MSFG transformation automatically or interactively, following functions have been implemented in the system. (1) MSFG transformation and identities, (2) Simulation of MSFG response, (3) Verification of the transformed MSFG, (4) Complexity information of MSFG. To demonstrate the usefulness and the effectiveness of the system, some design examples have been given in chapter 5. In these examples, step-by-step MSFG transformations are provided, which would otherwise be very difficult or extremely tedious to derive