INGINERIA FILTRELOR ACTIVE RC SI ZGOMOTUL ELECTRONIC

Autor/autori: Prof. dr. ing. Valentin GUTU (republica Moldova)

Rezumat: Aceasta lucrare este dedicata analizei rezultatelor metodei de calcul si a masurarilor experimentale a zgomotului propriu al dispozitivelor si echipamentelor electronice de selectie a semnalelor prin frecventa – filtrele active RC, schemele Sallen-Key, Teylor si Raukh. Aceste scheme de realizare permit obtinerea functiilor de transfer trece-sus (FTS), trece-jos (FTJ) si trece-banda (FTB). Sunt prezentate si analizate rezultatele calculelor teoretice si a masurarilor experimentale a zgomotului propriu al elementelor filtrelor active – amplificatoarelor operationale, este studiata influenta componentelor pasive si a factorului de calitate ale unui etaj de filtrare de ordinul doi in schemele mentionate. Analiza confirma posibilitatea utilizarii practice a metodei de calcul si de masurare a densitatii spectrale a zgomotului propriu si permite elaborarea unor recomandari principial noi pentru asamblarea filtrelor active RC, cu nivel scazut de zgomot.

Cuvinte cheie: filtre active, functie de transfer trece-jos, trece-sus, trece-banta, amplificator operational, zgomot propriu, caracteristici de zgomot, densitatea spectrala.

Abstract: This paper is dedicated to the analysis rezults of calculation method and experimental measurement of own noise of electronic devices and equipment for signals selection by frequency - the RC active filters, Sallen-Key, Teylor and Raukh version. This scheme allows the realization of active filters to obtain the transfer function high-pass (HPF), low-pass (LPF) and pass-band (PBF). Are prezented and analysed the rezults of teoretical calculations and experimental measurements of its noise active filter elements - the operational amplifiers, is studied the influence of passive coponents and the quality factor of a second order filter floor in the schemes mentioned. Analysis confirms the practical possibility of using the method of calculation and measurement of its noise spectral density and allows the development of fundamentally new recomendations for active filters assembly, with low noise.

Keywords: active filter, pass-low, pass-high, pass-band transfer function, operational amplifier, own noise, noise caracteristics, spectral density

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