Survey of excitation signals for FFT based signal analyzers
TL;DR: The properties of ten different excitation signals are studied to analyze their suitability as excitation signal for fast Fourier transform (FFT)-based signal and network analyzers and the flexibility to create a customized amplitude spectrum is investigated.
Abstract: The properties of ten different excitation signals are studied to analyze their suitability as excitation signals for fast Fourier transform (FFT)-based signal and network analyzers. Their influence on the measurement time, accuracy, and sensitivity to nonlinear distortions is described. The flexibility to create a customized amplitude spectrum is investigated. With this information it becomes possible to select the best excitation signal for many applications. >
Citations
More filters
Journal Article•
TL;DR: In this article, the transfer function measurements using sweeps as excitation signals rather than pseudonoise signals have been investigated and shown to have significantly higher immunity against distortion and time variance.
Abstract: Transfer-function measurements using sweeps as excitation signals rather than pseudonoise signals show significantly higher immunity against distortion and time variance. Capturing binaural room impulse responses for high-quality auralization purposes requires a signal-to-noise ratio (SNR) greater than 90 dB, which is unattainable with maximum-length sequence (MLS) measurements because of loudspeaker nonlinearity, but it is fairly easy to reach with sweeps due to the possibility of complete rejection of harmonic distortion. Before investigating the differences and practical problems of measurements with MLS and sweeps and arguing why sweeps are the preferable choice for the majority of measurement tasks, the existing methods of obtaining transfer functions are reviewed. The continual need to use preemphasized excitation signals in acoustical measurements is also addressed. A method to create sweeps with arbitrary spectral contents, but constant or prescribed frequency-dependent temporal envelope, is presented. Finally, the possibility of simultaneously analyzing transfer functions and harmonics is investigated.
445 citations
TL;DR: A new crest-factor minimization algorithm is presented for periodic signals with prescribed power spectrum based on approximation of the nondifferentiable Chebyshev (minimax) norm by l/sub p/-norms with increasing values of p, and the calculations are accelerated by using FFTs.
Abstract: Low crest-factor of excitation and response signals is desirable in transfer function measurements, since this allows the maximization of the signal-to-noise ratios (SNRs) for given allowable amplitude ranges of the signals. The authors present a new crest-factor minimization algorithm for periodic signals with prescribed power spectrum. The algorithm is based on approximation of the nondifferentiable Chebyshev (minimax) norm by l/sub p/-norms with increasing values of p, and the calculations are accelerated by using FFTs. Several signals related by linear systems can also be compressed simultaneously. The resulting crest-factors are significantly better than those provided by earlier methods. It is shown that the peak value of a signal can be further decreased by allowing some extra energy at additional frequencies. >
222 citations
TL;DR: The selection of topics and the organization of the discussion are strongly colored by the personal journey of the authors in this nonlinear universe.
Abstract: Nonlinear system identification is an extremely broad topic, since every system that is not linear is nonlinear. That makes it impossible to give a full overview of all aspects of the fi eld. For this reason, the selection of topics and the organization of the discussion are strongly colored by the personal journey of the authors in this nonlinear universe.
220 citations
Cites background from "Survey of excitation signals for FF..."
...Such a signal is called a multisine [148], and it has a period / T f 1 0 = and a frequency resolution f0 = / / ....
[...]
TL;DR: It is argued that the GBN concept indeed gives much better identification results than the conventional concept, considering the stochastic features of GBN and an analytical result on optimal GBN design for stable, first-order processes is presented.
150 citations
TL;DR: A state-of-the-art comprehensive review and up-to-date progress of the offline and online parameter estimation techniques of the permanent magnet synchronous motor drives.
Abstract: Permanent magnet synchronous motor (PMSM) drive has emerged as one of the most preferred motor drives for industrial applications owing to its distinguished advantages, such as high torque density, high efficiency, and wide speed range operation. However, accurately updated knowledge about the PMSM parameters is crucial to designing a high-performance trajectory tracking controller. This article presents a state-of-the-art comprehensive review and up-to-date progress of the offline and online parameter estimation techniques of the PMSM drives. First, the problems associated with parameter estimation of the PMSM are systematically summarized to identify the parameters having fast and accurate convergence. Second, the offline parameter estimation techniques are categorized based on the frequency and time responses. Third, the recent advances and developments of the online parameter estimation techniques for PMSMs are assessed. Finally, there is a discussion of extensive industrial applications and future research trends for the parameter estimation techniques.
110 citations
References
More filters
01 Jan 1978
TL;DR: A comprehensive catalog of data windows along with their significant performance parameters from which the different windows can be compared is included, and an example demonstrates the use and value of windows to resolve closely spaced harmonic signals characterized by large differences in amplitude.
Abstract: This paper makes available a concise review of data windows and their affect on the detection of harmonic signals in the presence of broad-band noise, and in the presence of nearby strong harmonic interference. We also call attention to a number of common errors in the application of windows when used with the fast Fourier transform. This paper includes a comprehensive catalog of data windows along with their significant performance parameters from which the different windows can be compared. Finally, an example demonstrates the use and value of windows to resolve closely spaced harmonic signals characterized by large differences in amplitude.
7,130 citations
01 Jan 1974
TL;DR: A computer algorithm that computes the discrete Fourier transform much faster than other algorithms, is explained and examples and detailed procedures are provided to assist the reader in learning how to use the algorithm.
1,823 citations
TL;DR: In this correspondence, a formula for the phase angles is derived that yields generally low peak factors, often comparable to that of a sinusoidal signal of equal power.
Abstract: This correspondence considers the problem of how to adjust the phase angles of a periodic signal with a given power spectrum to minimize its peak-to-peak amplitude. This "peak-factor problem" arises in radar, sonar, and numerous other applications. However, in spite of the wide-spread interest it has evoked, the peak-factor problem has so far defied solution except in cases where the number of spectral components is small enough to permit an effectively exhaustive search of all phase angle combinations. In this correspondence, a formula for the phase angles is derived that yields generally low peak factors, often comparable to that of a sinusoidal signal of equal power. A formula is also derived for the case in which the phase angles are restricted to 0 and \pi . The latter formula is applicable to the problem of constructing binary sequences of arbitrary length with Iow autocorrelation coefficients for nonzero shifts.
724 citations
"Survey of excitation signals for FF..." refers background in this paper
...Schroeder [ 3 ] gives a simple solution to the problem....
[...]
TL;DR: In this paper, an algorithm is presented to minimize the peaks in the time domain of bandlimited Fourier signals, which has the ability to compress signals effectively without disturbing their spectral magnitudes.
Abstract: An algorithm is presented to minimize the peaks in the time domain of bandlimited Fourier signals. This method has the ability to compress signals effectively without disturbing their spectral magnitudes. A computationally efficient algorithm is presented that leads to strongly compressed signals (crestfactors of 1.41 compared to 1.67). The method is applicable not only to flat spectrum magnitudes but to any frequency domain energetic distribution. >
183 citations
"Survey of excitation signals for FF..." refers background or methods in this paper
...The phase of the frequency components is optimized to reduce the crest factor of the signal 131, [ 4 ]....
[...]
...2) Swept Sine: Also called periodic chirp [ 11, [ 4 ]....
[...]
...same iterative algorithm as the optimization scheme of Van Der Ouderaa [ 4 ] and Van den Bos [ 111 for the multisine....
[...]
...Van der Ouderaa proposed an iterative solution for the optimization problem [ 4 ]....
[...]
...More details can be found in [ 4 ] and the corresponding signal will be called a VDO....
[...]