Measurement of Noise in Electronic Devices by the Fourier Transform Method

The paper considers and analyzes the method of measuring the noise characteristics of electronic circuits and devices based on data collection by a digital oscilloscope with a built-in Fourier transform. The measurement process methodology and its analysis are demonstrated when determining the noise characteristics of industrial resistors. This includes, in particular, thermal (white) noise, which is the predominant type of resistor noise. The work includes an overview of the noise properties of resistors and existing measurement methods, as well as an understanding of the theory of such measurements. To determine the sources of noise in industrial resistors, a real-time fast Fourier transform (FFT) of the signal was run on an oscilloscope. Thermal (white) noise spectra were determined using the FFT tool using a total number of 212 points.. However, it is difficult to make any recommendations as to which setup should be used for a particular resistor type or technology, as for most setups the noise level is unknown and only a few measurement results are available. The ratio of the average value of the power spectral density (PSD) of thermal noise in the frequency range of measurements to its calculated theoretical value based on the ohmic rating of the measuring coal industrial resistors was estimated.