ENGINEERING TRIPOS PART II A and EIST I

EIET LABORATORY ENGINEERING AREA ACTIVITY

Areas 5,6,7 and 8

INVESTIGATION OF THE DESIGN OF CD PLAYERS

SUBTOPIC: DEMODULATION AND ERROR CONTROL CODING

1. INTRODUCTION

In the CD player, the signal is read from the disk by an electro-optical front end, and then after amplification and filtering by front-end electronics, the resulting electronic signal is fed into the SAA7310 decoder IC. This powerful IC demodulates the signal (and in the process extracts bit-timing information which is used to control the disc rotation speed), and then it performs the major task of decoding the signal and applying error correction.

The main aim of this exercise is for you investigate the performance of the demodulation and error control coding functions, and explain why they have been designed the way they have.

To do this, you will need to draw on a number of sources of information. You may also want to use some custom electronics which we have designed to let you "get at" some relevant signals inside the CD player.

The main sources of useful information are likely to be: