# Time-frequency analysis of non-stationary fusion plasma signals using an improved Hilbert-Huang transform

## Abstract

An improved Hilbert-Huang transform method is developed to the time-frequency analysis of non-stationary signals in tokamak plasmas. Maximal overlap discrete wavelet packet transform rather than wavelet packet transform is proposed as a preprocessor to decompose a signal into various narrow-band components. Then, a correlation coefficient based selection method is utilized to eliminate the irrelevant intrinsic mode functions obtained from empirical mode decomposition of those narrow-band components. Subsequently, a time varying vector autoregressive moving average model instead of Hilbert spectral analysis is performed to compute the Hilbert spectrum, i.e., a three-dimensional time-frequency distribution of the signal. The feasibility and effectiveness of the improved Hilbert-Huang transform method is demonstrated by analyzing a non-stationary simulated signal and actual experimental signals in fusion plasmas.

- Authors:

- Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

- Publication Date:

- OSTI Identifier:
- 22308675

- Resource Type:
- Journal Article

- Resource Relation:
- Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; FREQUENCY ANALYSIS; OSCILLATION MODES; PLASMA; REGRESSION ANALYSIS; SIGNALS; SIMULATION; SPECTRA; THREE-DIMENSIONAL CALCULATIONS; TIME DEPENDENCE; TOKAMAK DEVICES

### Citation Formats

```
Liu, Yangqing, E-mail: liuyq05@gmail.com, Tan, Yi, Xie, Huiqiao, Wang, Wenhao, and Gao, Zhe.
```*Time-frequency analysis of non-stationary fusion plasma signals using an improved Hilbert-Huang transform*. United States: N. p., 2014.
Web. doi:10.1063/1.4887415.

```
Liu, Yangqing, E-mail: liuyq05@gmail.com, Tan, Yi, Xie, Huiqiao, Wang, Wenhao, & Gao, Zhe.
```*Time-frequency analysis of non-stationary fusion plasma signals using an improved Hilbert-Huang transform*. United States. doi:10.1063/1.4887415.

```
Liu, Yangqing, E-mail: liuyq05@gmail.com, Tan, Yi, Xie, Huiqiao, Wang, Wenhao, and Gao, Zhe. Tue .
"Time-frequency analysis of non-stationary fusion plasma signals using an improved Hilbert-Huang transform". United States.
doi:10.1063/1.4887415.
```

```
@article{osti_22308675,
```

title = {Time-frequency analysis of non-stationary fusion plasma signals using an improved Hilbert-Huang transform},

author = {Liu, Yangqing, E-mail: liuyq05@gmail.com and Tan, Yi and Xie, Huiqiao and Wang, Wenhao and Gao, Zhe},

abstractNote = {An improved Hilbert-Huang transform method is developed to the time-frequency analysis of non-stationary signals in tokamak plasmas. Maximal overlap discrete wavelet packet transform rather than wavelet packet transform is proposed as a preprocessor to decompose a signal into various narrow-band components. Then, a correlation coefficient based selection method is utilized to eliminate the irrelevant intrinsic mode functions obtained from empirical mode decomposition of those narrow-band components. Subsequently, a time varying vector autoregressive moving average model instead of Hilbert spectral analysis is performed to compute the Hilbert spectrum, i.e., a three-dimensional time-frequency distribution of the signal. The feasibility and effectiveness of the improved Hilbert-Huang transform method is demonstrated by analyzing a non-stationary simulated signal and actual experimental signals in fusion plasmas.},

doi = {10.1063/1.4887415},

journal = {Review of Scientific Instruments},

number = 7,

volume = 85,

place = {United States},

year = {Tue Jul 15 00:00:00 EDT 2014},

month = {Tue Jul 15 00:00:00 EDT 2014}

}