RAPID CLOCK RECOVERY ALGORITHMS FOR DIGITAL MAGNETIC RECORDING AND DATA COMMUNICATIONS

Abstract

The 1990's may well be considered as the era of information technology, with the prevalence of computers, digital communications and hence the need for data storage. Diverse data storage media have been introduced, such as silicon (flash memory) [3] and the CD (Compact Disk) [4], however improvements in magnetic recording has resulted in magnetic media as the prominent leader in mass storage technology. With improvements to the storage medium, the read/write heads and the channel electronics, the capacity of magnetic rigid disks has approximately doubled every 3 years (period 1960-90) [5]. These improvements to the channel, coupled with fast data-access times, has resulted in the magnetic disk drive remaining the dominant data storage device in computer technology. As storage densities increased, digital audio became viable and, driven by the enormous consumer market, products such as the audio CD [6] and RDAT (Rotary Head Digital Audio Tape) [7] have taken over from their analogue counterparts, as state of the art digital recording. Data communications is another huge growth area, with satellite data communications providing exciting new applications such as MPEG-2 (Motion Pictures Expert Group) compressed digital TV [8], Internet access [9] and personal communications [10].