R. A. Rohrbaugh, "Application of time-frequency analysis to machinery condition assessment", in Proc. 27th Asilomar Conference on Signals, Systems, and Computers, November 1993.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....frequency components. Attractive alternatives to the Fourier transform are the Wigner Ville transform, the wavelet transform, and the higher order spectral transform. The Wigner Ville transform has been previously used in analyzing manufacturing signals, including surface signals (Boashash, 1992; Rohrbaugh, 1993; Whitehouse and Zheng, 1992) However, 2 Copyright c fl 1997 by ASME this transformation typically introduces redundant features that obscure the significant fault features. The wavelet transform has been used in a number of signal processing applications, including a few manufacturing ....

Rohrbaugh, R. A., 1993. Application of time-frequency analysis to machinery condition assessment. In The twentyseventh Asilomar Conference on Signals, Systems, & Computers, volume 2, pages 1455--1458.

....possess certain nuisance parameters which have to be incorporated in the design of detectors. For example, in radar the targets have unknown delay Doppler, and in machine health monitoring, the fault signals occur at unknown time offsets and often exhibit unknown or random frequency shifts [1, 2, 3]. The need for detection in such nonstationary scenarios has spurred a great deal of interest in time frequency based detection schemes [1, 2, 4, 3, 5] Time frequency representations (TFRs) are a versatile set of tools for the analysis and processing of nonstationary signals [6] They are ....

.... delay Doppler, and in machine health monitoring, the fault signals occur at unknown time offsets and often exhibit unknown or random frequency shifts [1, 2, 3] The need for detection in such nonstationary scenarios has spurred a great deal of interest in time frequency based detection schemes [1, 2, 4, 3, 5]. Time frequency representations (TFRs) are a versatile set of tools for the analysis and processing of nonstationary signals [6] They are overparameterized signal representations in terms of time and frequency, and describe the nonstationary signal characteristics via their time varying This ....

R. A. Rohrbaugh, "Application of time-frequency analysis to machinery condition assessment", in Proc. 27th Asilomar Conference on Signals, Systems, and Computers, November 1993.

....and the Schlumberger Foundation. 1 Introduction Detection and estimation of signals in the presence of noise is an old and important problem in communications and signal processing. Applications include radar and sonar, and, more recently, automatic fault detection in machinery [1, 2, 3, 4, 5, 6]. Time frequency representations (TFRs) and time scale representations (TSRs) have been extensively used for detection in these and other applications, primarily due to the need for dealing with nonstationary signals. Drawing on certain properties of high resolution TFRs, a class of quadratic ....

....of the signal correlation function R TF or R TS characterizing the families fR ( s g or fR ( c) s g, respectively. For example, faults in rotating machinery typically exhibit transient, nonstationary signatures for which an appropriately chosen wavelet basis might be a good model [1, 2]. In such situations, ML estimates of the eigenvalues may be used for the various TFR TSR detectors. In order to characterize the TFR TSR detectors based on ML estimates of signal eigenvalues, it is very convenient to interpret the detectors as a weighted sum of a bank of spectrograms or ....

R. A. Rohrbaugh, "Application of time-frequency analysis to machinery condition assessment", in Proc. 27th Asilomar Conference on Signals, Systems, and Computers, November 1993.

....methods have long been used for detection in applications such as sonar and radar. More recently, extensive interest has arisen in time frequency based detection for new applications as diverse as machine fault detection, communications signal detection, and heart attack risk assessment from ECGs [1] [2] Time frequency methods are of interest because of the nonstationary nature of these signals or the interference. However, unlike the classical matched filter theory applied in radar and sonar, the methods developed for these new applications are ad hoc, with no assurance that the ....

R. A. Rohrbaugh, "Application of time-frequency analysis to machinery condition assessment", in Proc. 27th Asilomar Conference on Signals, Systems, and Computers, November 1993.

....using TFRs to get a visual display of the timevarying spectral energy in the signal and using this qualitative information as a starting point for further analysis processing. Recently though, the need for detection in nonstationary scenarios has spurred interest in the use of TFRs as detectors [2, 3, 4]. However, most of the proposed techniques are ad hoc and or do not justify the use of TFRs as detectors. Some very recent results have put TFR based detection theory on a firm footing [5] thereby extending the use of TFRs to more quantitative application. This work was supported by the Office ....

....signals, noise and interference. One promising framework is that of nonstationary signal detection in the presence of noise and interference, which has received substantial attention lately; for example, in applications such as radar sonar, engine knock detection [4] and machine health monitoring [3, 2]. Owing to the rich variety of signals involved in such applications, techniques beyond TFR based detection are desirable. In this paper, we present a framework for optimum detection based on any arbitrary class of generalized quadratic JSRs, thereby making it applicable in a broad class of ....

R. Rohrbaugh, "Application of time-frequency analysis to machinery condition assessment", in Proc. 27th Asil. Conf. on Signals, Systems, and Computers, November 1993.

....detection in nonstationary environments, recently there has been substantial interest in the use of time frequency and time scale representations (TFRs and TSRs) for detection. For example, TFR TSR based detection has been explored in mechanical diagnostics applications such as machine monitoring [1] and engine knock detection [2] More recently, a theoretical framework for optimal time frequency time scale detection has been developed that puts such primarily heuristic approaches on a firm footing [3] it characterizes the scenarios in which bilinear time frequency time scale detectors are ....

R. Rohrbaugh, "Application of time-frequency analysis to machinery condition assessment", in Proc. 27th Asil. Conf. on Signals, Systems, and Computers, November 1993.

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R. A. Rohrbaugh, "Application of time-frequency analysis to machinery condition assessment", in Proc. 27th Asilomar Conference on Signals, Systems, and Computers, November 1993.

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R. Rohrbaugh, "Application of time-frequency analysis to machinery condition assessment", in Proc. 27th Asil. Conf. on Signals, Systems, and Computers, November 1993.

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R. Rohrbaugh, "Application of time-frequency analysis to machinery condition assessment", in Proc. 27th Asil. Conf. on Signals, Systems, and Computers, November 1993.

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