Milos Sedlacek

Interpolations in frequency and time domains used in FFT spectrum analysis

Abstract The paper describes two methods of leakage reduction in DFT spectrum analysis using interpolation techniques — interpolation and resampling in the time domain (I/RTD) and windowing and interpolation in the frequency domain (W/IFD). Basic properties of both methods are summarized and compared and the efficiency of the methods is demonstrated both on sinusoidal and a multitone signals. Results of both computer simulations and measurements using common DAQ PC plug-in boards are presented. Using a combination of both methods is suggested as a possible alternative to the strict signal/sampling synchronization prescribed in international standards for instrumentation suggested for harmonic component analysis in LF EMC measurements when no windowing is used.

Comparison of nonparametric frequency estimators

This paper deals with the performance of several up-to-date nonparametric frequency estimators. The algorithms of frequency estimation are introduced and their bias, standard deviation and consumption time are compared with regard to the most common signal parameters.

Testing of statistical analyzers

Abstract The purpose of this paper is to describe methods of finding errors of instruments measuring the amplitude probability distribution of signals. Definitions of errors are introduced and testing using periodical and pseudo-random test signals is described. Some illustrative experimental results are shown from which it can be seen that the errors of statistical analyzers depend on the type of test signal used. The cause of this fact is explained. The merits of sinusoidal, saw-tooth and pseudo-random test signals are compared and the use of a sinusoidal signal with slight overrange or software correction of marginal parts of the error curves is recommended for the comparison of the accuracy of different types of statistical analyzers.