Estimating Method of the Spectrum Measurement Error Caused by the ADC Quantization Noiset

Abstract

Currently, the method of spectrum measurement based on the application of discrete Fourier transform (DFT) is the most popular. To perform DPF, the input signal must be discrete, which implies the presence of an analog-to-digital converter (ADC) in the measuring channel. Resolution of any ADC is finite, and it is create the quantization error. The error of ADC quantization results to additional measurement error of amplitude and phase spectrum. The simulation results show that the existing methods of estimation of this error results to a significant overstatement of the evaluation value. The paper considers a new technique (the “composite” method) of estimating the measurement error of amplitude spectrum caused by the ADC quantization noise. The proposed method is based on approximation of the spectrum of the ADC output signal (code) by a simple analytical function. Analytical expressions which allow for a given input signal, ADC chip and sample rate to estimate the measurement error of the signal spectrum caused by the ADC quantization noise are obtained. The comparison of the proposed method of error estimation with the existing methods is performed. Simulation results are obtained in Matlab software package.