A Study of Double-Sided Intersymbol Interference in Digital Data Communication Systems

摘要

Modern digital data communication systems demand a high rate of transmission and often use pulse amplitude modulation. These systems are useful only when the effects of intersymbol interference (ISI) and noise can be simultaneously reduced to the point where data transmission is 'reliable.' Systems where ISI is introduced in the current pulse by the pulses preceding it have been studied extensively but little attention has been given those systems in which the ISI is 'double-sided' (DSISI). That is, both past and future pulses contribute to the interference in the current pulse. One class of systems in which DSISI plays an important role consists of those systems which use magnetic data storage. Recent advances in the technology of large capacity data storage systems which use magnetic storage techniques have opened new areas of possible large scale digital data communication system applications. However, because of detection procedures that are currently being applied, the bit density of such systems is limited to approximately 1000 bits per inch (BPI). This research investigates two new methods by which the effects of DSISI can be eliminated or reduced in the above class of systems and develops error expressions or bounds by which the performance of these systems can be evaluated as a function of the bit density. (Author)