A 3.125 Gb/s limit amplifier in CMOS with 42 dB gain and 1 /spl mu/s offset compensation

A fast offset compensation method for high-gain amplifiers is presented that leverages a novel peak detector design and a dynamic, multi-tap feedback system to achieve roughly three orders of magnitude improvement in settling time over traditional compensation methods. Design tradeoffs between gain, bandwidth, power dissipation, and noise performance of the limit amplifier are discussed. Measured results of a custom 3.125 Gb/s limit amplifier in 0.18 /spl mu/m CMOS employing the proposed compensation technique demonstrate a sub-1-ms settling time while still achieving less than 4 ps rms output jitter with a 2.5 mV peak-to-peak input at 2.5 Gb/s.     

Parallel language developments in Europe: An overview

This article is concerned with the topic of parallel programming language design and implementation, with particular emphasis on the developments which are, and have been, taking place in Europe. Consideration is given to specific approaches to parallel programming with illustrative examples taken from projects which have been carried out in Europe. The paper is based on a report prepared for the European Commission during 1990.     

Languages for vector and parallel processors

This paper first considers the major developments which have occurred in the design of high level languages for sequential machines. These developments illustrate how languages which were independent of the hardware eventually evolved. Two major types of language for vector and parallel processors have evolved, namely, detection of parallelism languages and expression of machine parallelism languages. The disadvantages and advantages of each type of languages are examined. A third type of language is also considered which reflects neither the compiler's detection mechanism nor the underlying hardware. The syntax of this language enables the parallel nature of a problem to be expressed directly. The language is thus appropriate for both vector and array processors.     

A 12-Bit, 10-MHz Bandwidth, Continuous-Time $SigmaDelta$ ADC With a 5-Bit, 950-MS/s VCO-Based Quantizer

The use of VCO-based quantization within continuous-time (CT) SigmaDelta analog-to-digital converter (ADC) structures is explored, with a custom prototype in 0.13 mum CMOS showing measured performance of 86/72 dB SNR/SNDR with 10 MHz bandwidth while consuming 40 mW from a 1.2 V supply and occupying an active area of 640 mum times 660 mum. A key element of the ADC structure is a 5-bit VCO-based quantizer clocked at 950 MHz which achieves first-order noise shaping of its quantization noise. The quantizer structure allows the second-order CT SigmaDelta ADC topology to achieve third-order noise shaping, and direct connection of the VCO-based quantizer to the internal DACs of the ADC provides intrinsic dynamic element matching of the DAC elements.     

e-Science Infrastructure for Digital Media Broadcasting

Because digital media management and distribution technologies face some of the same challenges that e-Science aims to address, this technology is a viable solution to meet the broadcasting domain's rigorous demands.     

An experiment with Fortran and Pascal

This paper reports on a programming experiment involving the languages Fortran and Pascal. The subject of the experiment was the simulation of the X-ray department of a local hospital. The programming was carried out by two different programmers at different periods of time. A static analysis was performed on both models to determine how the languages were used by both programmers. The compilation and execution speeds of both models were then determined when executed on an ICL 1906S computer. The results indicate that the Pascal program is substantially faster in both compilation and execution speed than an equivalent Fortran program.     

An efficient approach to ARMA modeling of biological systems withmultiple inputs and delays

Presents a new approach to AutoRegressive Moving Average (ARMA or ARX) modeling which automatically seeks the best model order to represent investigated linear, time invariant systems using their input/output data. The algorithm seeks the ARMA parameterization,which accounts for variability in the output of the system due to input activity and contains the fewest number of parameters required to do so. The unique characteristics of the proposed system identification algorithm are its simplicity and efficiency in handling systems with delays and multiple inputs. The authors present results of applying the algorithm to simulated data and experimental biological data. In addition, a technique for assessing the error associated with the impulse responses calculated from estimated ARMA parameterizations is presented. The mapping from ARMA coefficients to impulse response estimates is nonlinear, which complicates any effort to construct confidence bounds for the obtained impulse responses. Here a method for obtaining a linearization of this mapping is derived, which leads to a simple procedure to approximate the confidence bounds     

Assessment of the relative agronomic effectiveness of phosphate rocks under glasshouse conditions

Six phosphate rocks (PRs) of varying reactivities were compared with monocalcium phosphate (MCP) in a glasshouse experiment growing perennial ryegrass (Lolium perenne cv. Nui) as the test plant on four soils of contrasting P sorption capacity and exchangeable Ca. The cumulative dry matter yield over 10 harvests showed a significant response to P application in all soils. Based on relative yield and P uptake, MCP was the most effective P fertilizer followed by the reactive phosphate rocks, which were superior to the unreactive rocks in all soils. The relative agronomic effectiveness (RAE) and substitution ratio (SR) of individual PR fertilizers, calculated with respect to MCP using the methods of vertical and horizontal comparison, respectively, were similar over a range of fertilizer rate. There was a decline or slight increase in the performance of PRs with time in the low P sorption soils but a consistent increase in the high P sorption soils. Some initial influence of exchangeable Ca content of the soils on the relative performance of PRs was also observed. Generally the PRs performed better in high P sorption soils than low P sorption soils and in low exchangeable Ca soils than high exchangeable Ca soils.