Static and Dynamic Nonlinearity of A/D Converters

The dynamic range of broadband digital system is mostly limited by harmonics and spurious arising from ADC nonlinearity. The nonlinearity may be described in several ways. The distinction between static and dynamic contributions has strong theoretical motivations but it is difficult to independently measure these contributions. A more practical approach is based upon analysis of the complex spectrum, which is well defined, easily measured, and may be used to optimize the ADC working point and to somehow characterize both static and dynamic nonlinearity. To minimize harmonics and spurious components we need a sufficient level of input noise (dither), which destroys the periodicity at multistage pipelined ADC, combined with a careful analysis of the different sources of nonlinearity

The use of simulation to prepare and improve responses to infectious disease outbreaks like COVID-19: practical tips and resources from Norway, Denmark, and the UK.

In this paper, we describe the potential of simulation to improve hospital responses to the COVID-19 crisis. We provide tools which can be used to analyse the current needs of the situation, explain how simulation can help to improve responses to the crisis, what the key issues are with integrating simulation into organisations, and what to focus on when conducting simulations. We provide an overview of helpful resources and a collection of scenarios and support for centre-based and in situ simulations

A Simple Method of Measuring the Noise Figure of the NMR Spectometer

Sensitivity is one of the fundamental parameters of the Nuclear Magnetic Resonance experiment. It depends particularly on the coil and impedance matching of the resonance circuit of the probe to the input amplifier. However, sensitivity is also influenced by the noise of the receiver of the spectrometer, and the insertion loss of the matching and switching circuits as well as of passive fillers inserted in front of the input preamplifier manifests itself markedly. In this paper, a simple method of measuring the noise figure feasible in the NMR laboratory is described. Using non-standard probes and coils, the measurement of the noise figure enables one to estimate to what degree the detection system itself participates in the signal/noise ratio deterioration. The method can be used also for measurements of other radio-frequency signal processing systems