COMPARISON BETWEEN DIFFERENT SOLUTIONS IN SPECTRUM ANALYSIS

Abstract – In this paper the conventional equally spaced sampling technique for spectrum analysis is compared to an asynchronous random sampling strategy, which has been previously proposed by authors for other broadband digital instrumentation. To this aim, two new approaches to the per-formance analysis are exploited, both being characterised by the fact that no classical DFT algorithms are applied. In the first method, the analytical expression for the estimate of signal harmonic components is defined as a direct approxi-mation of the Fourier series coefficients and the parameters that characterise the measurement accuracy associated with the considered sampling strategy are deduced. Following the second approach, the spectral component estimates are treated as random variables, due to the presence in their op-erative definition of unknown parameters that can be inter-preted as stochastic. The expected value and variance are deduced for each harmonic estimate, in order to compare the properties of the two sampling strategies. Simulation results are proposed in order to validate the theoretical findings, showing an excellent agreement