System enables more complete calibrations of dynamic-pressure transducers

Absolute pressure calibration system using a Michelson interferometer calibrates phase characteristics and pressure sensitivities of the transducers that monitor acoustic or aerodynamic pressure fields. The interferometer uses a helium-neon laser light source and interchangeable acoustic signal generators to produce acoustic waves

Model reduction by matching the steady-state response of explicit signal generators

© 2015 IEEE.Model reduction by moment matching for interpolation signals which do not have an implicit model, i.e., they do not satisfy a differential equation, is considered. Particular attention is devoted to discontinuous, possibly periodic, signals. The notion of moment is reformulated using an integral matrix equation. It is shown that, under specific conditions, the new definition and the one based on the Sylvester equation are equivalent. New parameterized families of models achieving moment matching are given. The results are illustrated by means of a numerical example

Model-based pre-distortion for Signal Generators

Las señales espectralmente puras son un requisito indispensable cuando el generador de señales (SG) se va a utilizar como parte de un banco de pruebas. Sin embargo, incluso los equipos sofisticados pueden no cumplir con las necesidades impuestas por ciertas aplicaciones. Este trabajo aborda el problema mediante el uso de la distorsión digital previa (DPD) basada en un modelo polinómico sin memoria obtenido para la SG. Usando la SG en modo arbitrario (ARB), una señal de entrada es generada por computadora y reproducida por la SG. La precisión de la medición se garantiza mediante el muestreo de coherencia y la coincidencia de cuadrícula con el analizador de señal (SA). Finalmente, se utiliza una cuidadosa alineación temporal para comparar las señales de tres tonos transmitidas y recibidas para obtener los coeficientes de los polinomios. Los resultados muestran que la precisión del modelo y la efectividad de la distorsión previa pueden variar según la amplitud de la señal de tres tonos. Sin embargo, utilizando polinomios de 5º y 9º grados hasta 15dB de reducción de los productos de Intermodulación de 3er orden se pueden obtener, y los poderes espurios se pueden reducir a 70dBc.Spectrally pure signals are an indispensable requirement when the Signal Generator (SG) is to be used as part of a test bed. However, even sophisticated equipment may not comply with the needs imposed by certain applications. This work approaches the problem by using Digital Pre-Distortion (DPD) based on a polynomial memory-less model obtained for the SG. Using the SG in arbitrary mode (ARB) an input signal is computer-generated and reproduced by the SG. Measurement accuracy is ensured using coherence sampling and grid matching to the Signal Analyzer (SA). Finally, careful time alignment is used to compare the transmitted and received three-tone signals to obtain the polynomials coefficients. Results show that the accuracy of the model and the effectiveness of pre-distortion may vary depending on the amplitude of the three-tone signal. However, using polynomials of 5th and 9th degrees up to 15dB reduction of the 3rd order Inter-Modulation products can be obtained, and spurious powers may be lowered down to 70dBc.Suecia. Programa de intercambio sueco Linnaeus-PalmeTesi

Self-oscillations in field emission nanowire mechanical resonators: a nanometric DC-AC conversion

We report the observation of self-oscillations in a bottom-up nanoelectromechanical system (NEMS) during field emission driven by a constant applied voltage. An electromechanical model is explored that explains the phenomenon and that can be directly used to develop integrated devices. In this first study we have already achieved ~50% DC/AC (direct to alternative current) conversion. Electrical self-oscillations in NEMS open up a new path for the development of high speed, autonomous nanoresonators, and signal generators and show that field emission (FE) is a powerful tool for building new nano-components

Electronic Three-Phase Wave Generator

The present invention relates to electric signal generators, and more particularly to an electronic three-phase Wave generator

ARM MCU-Based Experimental EEG Signal Generator Using Internal DAC and PWM Outputs

Electrophysiological signal generators are widely used in biomedical engineering research, biomedical education and the testing of devices in hospitals. Such signal generators are also available commercially. The EEG (Electroencephalography) signal is an electrophysiological signal which is emitted from the brain. In this study, a signal generator that produces experimental EEG signals taken from databases is proposed. The proposed signal generator reads the experimental data from an SD card with SDIO serial protocol. In addition, the PWM and DAC outputs of the microcontroller are used and examined separately to generate the signal. It has been shown that the experimental signals taken from the database can be generated by using cheap and easily accessible electronic devices. © 2022, Gazi Universitesi. All rights reserved

Sampling from a system-theoretic viewpoint: Part II - Noncausal solutions

This paper puts to use concepts and tools introduced in Part I to address a wide spectrum of noncausal sampling and reconstruction problems. Particularly, we follow the system-theoretic paradigm by using systems as signal generators to account for available information and system norms (L2 and L∞) as performance measures. The proposed optimization-based approach recovers many known solutions, derived hitherto by different methods, as special cases under different assumptions about acquisition or reconstructing devices (e.g., polynomial and exponential cardinal splines for fixed samplers and the Sampling Theorem and its modifications in the case when both sampler and interpolator are design parameters). We also derive new results, such as versions of the Sampling Theorem for downsampling and reconstruction from noisy measurements, the continuous-time invariance of a wide class of optimal sampling-and-reconstruction circuits, etcetera