Signal Analysis for the Condition Monitoring of a Check Valve Using a Time-Frequency Representation

2004 ◽  
Vol 270-273 ◽  
pp. 209-214
Author(s):  
C.K. Lee ◽  
Dai Bum Cha ◽  
Jung Taek Kim ◽  
Joo Sun Kim ◽  
Sang J. Lee ◽  
...  
Keyword(s):  
Condition Monitoring ◽  
Signal Analysis ◽  
Check Valve ◽  
Time Frequency ◽  
Frequency Representation

scholarly journals Evaluation of Seven Time-Frequency Representation Algorithms Applied to Broadband Echolocation Signals

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Josefin Starkhammar ◽  
Maria Hansson-Sandsten
Keyword(s):  
Signal Analysis ◽  
Time Difference ◽  
Frequency Difference ◽  
Transient Signals ◽  
Signal Component ◽  
Time Frequency ◽  
Exact Location ◽  
Frequency Representation ◽  
Different Types ◽  
Echolocation Signal

Time-frequency representation algorithms such as spectrograms have proven to be useful tools in marine biosonar signal analysis. Although there are several different time-frequency representation algorithms designed for different types of signals with various characteristics, it is unclear which algorithms that are best suited for transient signals, like the echolocation signals of echolocating whales. This paper describes a comparison of seven different time-frequency representation algorithms with respect to their usefulness when it comes to marine biosonar signals. It also provides the answer to how close in time and frequency two transients can be while remaining distinguishable as two separate signals in time-frequency representations. This is, for instance, relevant in studies where echolocation signal component azimuths are compared in the search for the exact location of their acoustic sources. The smallest time difference was found to be 20 µs and the smallest frequency difference 49 kHz of signals with a −3 dB bandwidth of 40 kHz. Among the tested methods, the Reassigned Smoothed Pseudo Wigner-Ville distribution technique was found to be the most capable of localizing closely spaced signal components.

Operating Investigation of Transmission Systems Using Advanced Time-Frequency Representations

2003 ◽  
Author(s):  
Min-Chun Pan ◽  
Jeng-Yi Huang
Keyword(s):  
Condition Monitoring ◽  
Dynamic Characteristics ◽  
Mechanical Systems ◽  
Test Rig ◽  
Transmission Systems ◽  
Shape Distribution ◽  
Time Frequency ◽  
Frequency Representation ◽  
Component Test ◽  
Electro Magnetic

This study aims at developing and implementing advanced time -frequency representation algorithms, i.e., Choi-William distribution, and cone-shape distribution, based on the spectrogram and the smoothed Wigner- Ville distribution to both improve time and frequency resolutions as compared with the spectrogram, and soothe interferences resulting from the Wigner-Ville distribution. Synthetic signals were designed to assess the effectiveness of these algorithms, and compare computing features of these schemes as well. A transmission-component test rig was built up to investigate dynamic characteristics of the gearbox, belt set and electro-magnetic brake during operation. Conducted experimentation highlights the justification of applying these advanced schemes in condition monitoring tasks of mechanical systems.

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