Abstract

Abstract
In this paper, we present an application of the simulation annealing optimization algorithm to the problem of high-level synthesis of digital systems, targeted to architectures with run-time reconfigurable functional units. The scheduling, allocation and binding problems are treated simultaneously. Reconfiguration times and execution delays are taken into account, along with pipelined execution and precise clock cycles for consumption of each operand.

Abstract
Power supply current monitoring is a promising technique for the development of new test methodologies for analog and mixed-signal circuits. The advantages of efficiency and reduced test time have already been recognized in the digital domain. This paper shows that improved test efficiency and detection confidence are obtained when both output voltage and power supply current are observed. Results found from the simulation of two circuits are presented comparing fault detection ratios and the amplitude of faulty response deviations when observing each one of these signals. Cross-correlation between output voltage and power supply current is presented as a means to perform a single mixed current/voltage testing operation, providing at the same time increased efficiency. It allows also for simplifications on test circuitry and processing, as reductions on the sampling rates and amplitude resolutions used to acquire the signals provide the same fault coverage levels obtained using higher fidelity measurements.

Abstract
This work describes a video coder based on a hybrid DPCM-vector quantization algorithm that is suited for bit rates ranging from 8-16 kb/s, The proposed approach involves segmenting difference images into variable-size and variable-shape blocks and performing segmentation and motion compensation simultaneously, The purpose of obtaining motion vectors for variable-size and variable-shape blocks is to improve the quality of motion estimation, particularly in those areas where the edges of moving objects are situated, For the larger blocks, decimation takes place in order to simplify vector quantization, For very active blocks, which are always of small dimension, a specific vector quantizer has been applied, the fuzzy classified vector quantizer (FCVQ), The coding algorithm described displays good performance in the compression of test sequences at the rates of 8 and 16 kb/s; the signal-to-noise ratios obtained are good in both cases, The complexity of the coder implementation is comparable to that of conventional hybrid coders, while the decoder is much simpler in this proposal.

Abstract
The FM intermodulation characteristics of directly modulated semiconductor lasers of relevance to the design of subcarrier multiplexed applications are investigated. "Adiabatic" chirp which has previously not been considered is shown to have a large impact on the reduction of the distortion levels at frequencies below half the resonance frequency of the laser. Results are presented showing that, in contrast to previous suggestions, FM modulation may be advantageous, imposing less requirements on laser linearity than IM modulation.

Abstract
In this paper, we present an analytical approach to accurately assessing the performance of subcarrier multiplexed optical systems for the delivery of future mobile radio broadband services, The existence of a wide dynamic range of power levels in the return link, together with laser nonlinear distortion, represents a major problem and makes performance evaluation difficult. By modeling laser nonlinear distortion using Volterra series analysis, we show that the performance assessment of these systems becomes not only tractable, but also that they can be can be optimized based on the worst case condition, This analysis is performed here for the case of continuous phase frequency shift keying (CPFSK) modulation, for which we calculate the power spectral density (PSD) of the intermodulation products, The overall system performance is then investigated, and its dependence on laser bias and RIN is examined, As an illustrative example we consider a specific 50 channel CPFSK system occupying the bandwidth of 2 to 2.1 GHz.