Analysis and method for reducing the noise of a vertical channel of the sampling oscilloscope

Abstract

The approach to reduce the noise of a vertical channel of the sampling oscilloscope is presented in this paper. In general, the vertical channel of the sampling oscilloscope consists of a high-frequency sampling circuit and a relatively low-frequency sample transmission path along with a high bit resolution analog-to-digital converter. The paper presents the results of the analysis of the noise of the vertical channel of the sampling oscilloscope, considering y channel as a dynamic system whose parameters do not change over time. The analysis is performed in order to determine the ratio of the low-frequency path bandwidth of the vertical channel and the sampling frequency rate allowing the measurement system to remain in the ergodic state. By definition, an ergodic state of the oscilloscope vertical channel makes it possible to implement a channel noise reduction method which is based on an increase in the sampling rate of the output pulse of balance of the sampler, the amplitude of which is proportional to the accumulated charge of the sample of the measured signal. Our studies have shown that the state of the measuring system of the sampling oscilloscope corresponds to the ergodic one by increasing the sampling frequency to 10 MHz and, at the same time, it is possible to obtain a decrease in the signal-to-noise ratio almost two times.