A General Class of PAM Equalizers

This correspondence outlines a new and general class of cost functions which are applicable to adaptive PAM equalizer design. The new functions are shown to exhibit many of the features of well-known functions while promising lower receiver error probabilites. Further work in the area of relating cost functions to equalizer adaption rates is suggested.     

Electromagnetic fields and the quasistationary approximation near amoving mirror

A detailed study of the electromagnetic fields generated by illuminating a plane mirror, in inertial motion, by a plane wave is described. A new and complete power series is obtained for the fields, and convergence conditions depending on the distance between the mirror and an observer are established. This series is shown to converge in bandpass systems provided the distance between the mirror and the observer is limited. The power series provides simple expressions for assessing the validity of quasi-stationary (QS) field approximations near the mirror. An example confirms that, with the exception of the immediate vicinity of wavefronts, QS approximations are valid under conditions arising in practical urban radio systems     

Envelope Detection of Binary VSB Data Signals

The performance of vestigial-sideband data transmission systems employing envelope detection is considered in the context of broad-band local area networks (BLAN's). General results for horizontal and vertical eye opening are presented and noise performance is assessed for three systems of particular interest. It is concluded that this data transmission scheme is suitable for BLAN's.     

Aspects of PCM Regenerator Design for Crosstalk Limited Environments

The design of PCM regenerators for crosstalk limited environments is considered. A Regenerator Noise Figure is introduced and used to compare various regenerator equalizer designs. An optimum equalizer is derived to provide a basis for the comparison. The major conclusion is that cosine rolloff equalizers provide better crosstalk tolerance than Gaussian equalizers and that with particular rolloff factors they achieve near optimum performance. AMI, HDB3, and Class 4 partial response line codes are considered and results placed into practical context by examining regenerator eye diagrams.     

Mean square error of s.s.b.a.m. class 4 partial response data signals due to slope, sag and ripple group delay components

An expression is derived for the minimum mean square error of an s.s.b.a.m. data signal using class 4 partial response coding when distorted by a channel with group delay slope. This result supplements previously published results which describe the effects of group delay sag and ripple. It is shown that the total minimum mean square error from a combination of all three group delay components can be determined by adding the distortion from each component independently.     

Optimum p.c.m. regenerator performance in presence of crosstalk

Minimum values of p.c.m. regenerator NEXT noise figure and FEXT noise figure are derived. The performance of regenerators with optimised cosine rolloff is within 0.2 dB of these minima, and that of commercial regenerators can be within 2 dB of the minima.