Digital Audio Signal Processing, Second Edition

Chapter 4

Audio Processing Systems

Digital signal processors (DSPs) are used for discrete-time signal processing. Their architecture and instruction set is specially designed for real-time processing of signal processing algorithms. DSPs of different manufacturers and their use in practical circuits will be discussed. The restriction to the architecture and practical circuits will provide the user with the criteria necessary for selecting a DSP for a particular application. From the architectural features of different DSPs, the advantages of a certain processor with respect to fast execution of algorithms (digital filter, adaptive filter, FFT, etc.) automatically result. The programming methods and application programs are not dealt with here, because the DSP user guides from different manufacturers provide adequate information in the form of sample programs for a variety of signal processing algorithms.

After comparing DSPs with other microcomputers, the following topics will be discussed in the forthcoming sections:

• fixed-point DSPs;
• floating-point DSPs;
• development tools;
• single-processor systems (peripherals, control principles);
• multi-processor systems (coupling principles, control principles).

The internal design of microcomputers is mainly based on two architectures; the von Neumann architecture which uses a shared instruction/data bus; and the Harvard architecture which has separate buses for instructions and data. Processors based on these architectures are CISCs, RISCs ...