An Approach to the Implementation of a Discrete Cosine Transform

Abstract

An approach to the implementation of a di$crete cosine transform (DCT) for application to coding speech is described. The approach is oriented toward single speech channel encoding. In addition, a detailed computer simulation of an adaptive transform coder is described. The purpose of the computer simulation is to determine the internal precision at various points in the implementation required to avoid subjective degradation. Specific recommtnendations are made on the required internal precision in the implementation of the discrete cosine transform. A breadboard implementation of the DCT using SSI and MSI TTL logic based on the results of the computer simulation is reported.

Transform approach to split-band coding schemes

“…However, only the values in the first quadrant are required, since the other functions are obtainable via symmetry [11]. For a JV-point transform, JV fixed storage locations are needed.…”

A Discrete Fourier-Cosine Transform Chip

“…A VLSI chip realizing a small length DCT at very high speed is desirable, both for image coding and for discrete Fourier transform (DFT) evaluation. Implementations have been realized with assemblages of MSI hardware [5], [6], but, to our knowledge, VLSI implementations have only been proposed [7], [8]. The realized design described in this paper is not only different from the previously proposed ones, but its concepts can be easily extended to larger transform sizes and/or higher precision when finer mask design rules and associated chip processing become accessible.…”