Frequency estimation of a sinusoidal signal via a three-point interpolated DFT method with high image component interference rejection capability

Generalization of interpolation DFT algorithms and frequency estimators with high image component interference rejection

“…Recently, Belega et al proposed an improved threepoint IpDFT which exhibits a high rejection capability with respect to the interference from negative frequency [15]. In this paper, we proposed a novel frequency estimator by which the leakage coming from image component can be further reduced compared with the algorithm proposed by Belega et al More importantly, it also keeps good noise properties due to a two-point-based mechanism.…”

“…In fact, if signals contain a small number of cycles, the negative frequency component usually will exercise great influences on the estimators [15]. Although the multi-point IpDFT methods can reduce the sensitivity to some extent, frequency estimation errors due to the spectral interference from the image component still remain significant [15], especially for the signals with a few cycles. Furthermore, it should be emphasized that the reduction of systematic errors by the weighted interpolated DFT or multi-point IpDFT methods is at the expense of worse noise properties [9,12].…”

“…The approximation will be reasonable if λ 0 > 5 and λ 0 < N/2 − 5. However, if λ 0 were out of the specified ranges, significant errors would be generated [15]. Therefore, it is of great importance and necessary to deduce a simple algorithm that is applicable even when λ 0 is in the extreme ranges.…”

“…However, the algorithms mentioned above are all established on a very important assumption that the leakage coming from the image component plays a minor role and could be ignored [11][12][13]. In fact, if signals contain a small number of cycles, the negative frequency component usually will exercise great influences on the estimators [15]. Although the multi-point IpDFT methods can reduce the sensitivity to some extent, frequency estimation errors due to the spectral interference from the image component still remain significant [15], especially for the signals with a few cycles.…”

Iterative-Interpolated DFT for Synchrophasor Estimation: A Single Algorithm for P- and M-Class Compliant PMUs

“…The IpDFT problem solution has been originally provided as a 2-point interpolation scheme [17], [18]. More recently, multipoint interpolation schemes have demonstrated to inherently reduce the long-term spectral leakage effects, leading to more accurate interpolation results [10], [11]. In this respect, for the Hanning window, the fractional term δ can be computed by interpolating the 3 highest DFT bins as [10]:…”