Search results for "Gain measurement"
showing 3 items of 3 documents
Causal and Non-Causal Frequency Domain Assessment of Spontaneous Baroreflex Sensitivity after Myocardial Infarction
2020
Acute myocardial infarction (AMI) is thought to alter the baroreflex control of arterial pressure. We tested this hypothesis investigating the changes of the cardiovascular response after AMI in comparison with young and old healthy controls studied at rest and during head-up tilt, using causal and non-causal frequency domain measures of the baroreflex sensitivity. Our results indicate: (i) the importance of using a causal approach that takes into account not only feedback but also feedforward effects in the study of interactions between the heart period and the arterial pressure; (ii) the compromised capacity of baroreceptors to control SAP fluctuations in post-AMI patients, both at rest a…
DSP Implementation for Measuring the Loop Gain Frequency Response of Digitally Controlled Power Converters
2012
This paper presents a method for measuring the loop gain frequency response of digitally controlled power converters, without the need of any expensive measurement equipment such as frequency response analyzers (FRA). The method is based on the traditional perturbation and measurement scheme. The perturbation is internally synthesized by the DSP and applied as pulse-width modulation to the converter. The loop input and output data are sent to a PC via universal serial bus, which performs online the DFT of sent data. The perturbation amplitude is varied with frequency to improve signal-to-noise ratio of measurements. The number of cycles used to perform discrete Fourier transform calculation…
A novel noise figure and gain test set for microwave devices
2002
A new instrument for the measurement of noise and gain of microwave devices is presented. It differs from the commercial ones in the accomplishment of the gain measurement and is also useful for measuring mismatched devices such as transistors, The instrument is driven via HP-IB by a PC and a user-friendly virtual panel is designed to perform all the required operations. Also included is the possibility of removing the second-stage noise contribution and correcting various sources of error (source ENR variations, temperature variations, etc.). The test set provides a very good accuracy for both matched and mismatched devices, usually limited by source ENR accuracy and step attenuator repeat…