Abstract
Power supply current monitoring is a promising technique for the development of new test methodologies for analogue and mixed-signal circuits, following the success attained in the digital domain. This paper shows that improved test efficiency and confidence is obtained when both functional output voltage and power supply current signals are observed. Results obtained from simulation of a number of circuits are presented comparing Fault Coverage, Normalised Deviation, and the Coefficient of Variation of faulty responses deviation amplitudes. Also, different test stimuli are compared to evaluate their suitability for testing.

Abstract
This work uses Volterra kernels to model the distortion of complex optical systems using both frequency and intensity modulation of a DFB laser and an optical discriminator. The laser's IM and FM complex responses and also the laser's intrinsic FM distortion are shown to be crucial to model accurately the system's third-order intermodulation product (IMP3) performance. The results show that it is possible to achieve a large reduction of the third-order IMP3 in some frequency ranges by off-setting the bias of the discriminator from the point of maximum slope. Furthermore, at high frequencies the system's IMP3 performance can be better than in the case of a purely intensity modulated laser without a discriminator.

Abstract
The quality of low bit-rate coding algorithms standardized under ISO/MPEG has been carefully verified by subjective listening tests using audio material of the highest technical quality. When using digital audio compression in the context of television sound systems, however, the question arises, as to how the coders would perform with imperfect audio signals, such as those obtained from impaired film material. This paper describes studies into the effects of the more severe impairments present in film soundtracks upon MPEG-I Layer-2 and Layer-3 audio coding, which have been carried out within the European RACE `COUGAR' project programme R2122.

Abstract
Perceptual audio coders rely on the efficient reduction of perceptually irrelevant components of the audio signal as well as on the removal of statistical signal redundancies to achieve good coding gains. In order to reach high compression ratios without reducing the subjective quality of the encoded audio signal, it is necessary to identify critically interdependent functional units of the encoding algorithm and to jointly optimize their performance. A flexible and interactive simulation and analysis environment has been programmed to assist the development and optimization of a new perceptual audio coder. The main features of this environment will be explained and the most relevant aspects that were found to limit the encoding performance will be presented.

Abstract
ATM networks will support new multimedia services that will require new protocols. Those services and protocols will need different test strategies and tools. In this paper, the concepts of functional and non-functional testers of ATM networks are discussed, a multimedia service and its requirements are presented and, finally, a summary description of an ATM network and of the test tool that will be used to validate it are presented.

Abstract
This paper presents a Multimedia Art Directory, that has been developed for an ATM network, by describing its main characteristics and the creation environment and the network facilities used.