Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 54 for “"short time Fourier transform"”.
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Time-Frequency Analysis and Filtering based on the Short-Time Fourier Transform
The joint time-frequency (TF) domain provides a convenient platform for signal analysis by involving the dimension of time in the frequency representation of a signal. A straightforward way to acquire localized knowledge about the frequency content of the signal at different times is to perform the …
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Diphone Speech Synthesis Based on a Pitch-Adaptive Short-Time Fourier Transform
… techniques: (1) discrete pitch-adaptive short-time Fourier analysis, and (2) diphone representation of real speech.
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Application of signal estimation from the modified short-time Fourier transform to speech processing
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1985.
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Sparse separation of sources in 3D soundscapes
… novel application of a dual-tree complex wavelet transform to sparse source separation, providing an alternative transformation to the short-time Fourier transform often used in this area. Results are presented showing compara- ble signal-to-interference performance, and significantly improved …
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Shear Madness: Signal-Dependent and Metaplectic Time-Frequency Representations
Time-frequency representations are multidimensional transformations that indicate the joint time-frequency content of a signal. Representations such as the wavelet transform, the short-time Fourier transform, and the Wigner distribution have proven to be powerful tools for signal analysis and …
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Survey of free-field methods to measure the normal specific acoustic impedance of ground surfaces in situ at low frequencies
… and oblique incidence configurations. A new short-time Fourier transform technique is applied to the measured pressure data to reduce the variance of estimates. Credible estimates of the ground impedance are shown for frequencies as low as 30 Hz. Suggestions are made for future experiments.
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Statistical time-frequency analysis
Time-frequency representations (TFRs), such as the short-time Fourier transform, the wavelet transform, and the Wigner distribution, represent signal characteristics jointly in time and frequency and provide a versatile set of tools for the analysis and processing of nonstationary signals. Recent …
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Structural Damage Classification using Support Vector Machines
… crack and corrosion metallic damages using a time-frequency representation method and support vector machines is investigated. Piezoelectric ceramic actuators are utilized to generate guided wave signals on a set of aluminum beam coupons with different damage features, such as types, …
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Differential DSP: An audio toolbox for end-to-end ml
The short-time Fourier transform (STFT) has been a staple of signal processing, often being the first step for many audio tasks. A very familiar process when using the STFT is the search for the best STFT parameters, as they often have significant side effects if chosen poorly. These parameters are …
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A verification experiment of the second formant transition feature as a perceptual cue in natural speech
… two features within the consonantal release. Short Time Fourier Transform (STFT) modifications are made to consonant-vowel (CV) non-sense syllables to remove each of the tested acoustic features. Changes in listener response error are reported. An ANalysis Of VAriance (ANOVA)is used to …
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Phased Array Damage Detection and Damage Classification in Guided Wave Structural Health Monitoring
… to be useful, they are generally expensive, time consuming, and the results may not always be reliable. To overcome these drawbacks, structural health monitoring (SHM) systems has received significant attention in the past two decades. As structural systems are becoming more complicated and …
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PULSED RADAR TARGET RECOGNITION BASED ON MICRO-DOPPLER SIGNATURES USING WAVELET ANALYSIS
… rely on one among three different joint time-frequency transforms such as the short-time Fourier transform, the wavelet packet transform and the Haar transform to extract key μ-D signature related features from the time-frequency plane representation of the echo signal. These μ-D …
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Surface electromyography based speech recognition system and development toolkit
… rate of 5.77 kHz. Four feature sets, the short-time Fourier transform (STFT), the dual-tree complex wavelet transform (DTCWT), a non-causal time-domain based (E4-NC), and a causal version of E4-NC (E4-C) were implemented. Classification was performed using a hidden Markov model (HMM). The …
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Relationship between the autonomic nervous system and the recovering heart post exercise using heart rate variability
… (HRV) frequency spectrum. The recovery time was estimated by fitting an exponential curve to the heart rate post exercise where the exponent was used to calculate the time constant to indicate recovery time. A regression was then performed on the HF and recovery time in order to find a …
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Wavelet Scattering Transforms Applied to Whale Vocalisations
… the application of wavelet scattering transforms to whale vocalisations. We first consider how wavelet transforms can provide an alternative time-frequency decomposition for use in signal detectors. Detectors typically utilise the short-time Fourier transform (STFT), for which the …
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Study of Wavepacket Dynamics in Rubidium Vapor by Means of Time-Frequency Analysis
… are excited in rubidium vapor by intense ultrashort (∼100 fs) pulses centered at a wavelength of 620 nm or 770 nm. The generated atomic wavepackets are optically detected via a pump-probe experiment based on axially phase-matched parametric four-wave mixing (FWM). This nonlinear process …
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An approach for the separation of voices in composite musical signals
… events which may or may not be synchronized in time, frequency, and/or amplitude. Once the distinct events are combined and recorded in a storage medium, e.g., a digital recording, the composite signal is often unsatisfactory in some way: the recording might suffer from poor ensemble balance, …
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Radar-Based Multi-Target Classification Using Deep Learning
Real-time, radar-based human activity and target recognition has several applications in various fields. Examples include hand gesture recognition, border and home surveillance, pedestrian recognition for automotive safety and fall detection for assisted living. This dissertation sought to improve …
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Single-Microphone Speech Dereverberation: Modulation Domain Processing and Quality Assessment
… algorithms. Firstly, an upper bound of time-frequency masking (TFM) performance for dereverberation is obtained using ideal time-frequency masking (ITFM). ITFM has access to both the clean and reverberated speech signals in estimating the binary-mask matrix. ITFM implements binary …
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Micro-doppler classification of humans and animals using FMCW radar
… Alarm Rate (CFAR) maps for detection and using Short-Time Fourier Transform (STFT) for spectrogram generation were applied. Principal Component Analysis (PCA) was employed as the method for data reduction. The dataset was subsequently classified and evaluated across various target class …
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