نتایج جستجو برای: stft
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where w(n) is an analysis window. At each time instant, the STFT is a discrete-time Fourier transform or discrete Fourier transform (DFT). Many DFT computing algorithms and architectures have been proposed. However, the direct use of the DFI' without considering the special sliding window effect of STFT is not an efficient approach. There are two major approaches for STFT. One is based on the f...
Typical speech enhancement algorithms that operate in the Fourier domain only modify the magnitude component. It is commonly understood that the phase component is perceptually unimportant, and thus, it is passed directly to the output. In recent intelligibility experiments, it has been reported that the Short-Time Fourier Transform (STFT) phase spectrum can provide significant intelligibility ...
Filter banks with fixed time-frequency resolution, such as the Short-Time Fourier Transform (STFT), are a common tool for many audio analysis and processing applications allowing effective implementation via the Fast Fourier Transform (FFT). The fixed time-frequency resolution of the STFT can lead to the undesirable smearing of events in both time and frequency. In this paper, we suggest adapti...
Abstrac t This paper presents a procedure for wind speed measurement using ultrasonic transducers based on short-time Fourier transform (STFT). The measurement of wind speed was performed by estimating the ultrasonic transit-time (ToF). For this purpose the estimated ToF was used the technique of digital signal processing, based on the STFT. The ultrasonic signal detection was performed by sett...
در لرزهشناسی اکتشافی نشانگرهای طیفی لحظهای مانند بسامد مرکزی، بسامد ریشه میانگین مربعات (rms) و پهنای باند که بیشتر برای توصیف خواص وابسته به بسامد سنگها بهکار گرفته میشوند از نقشه زمان- بسامد (طیفنما) قابل استخراج هستند. این نشانگرها با استفاده از نظریه احتمال تعریف میشوند. طیفنما را میتوان از روشهای تبدیل فوریه زمان کوتاه (<span st...
This letter addresses the coherent integration problem for detecting high-speed target. A fast method based on short-time Fourier transform (STFT) and sequence reversing (SRT), that is, STFT-SRT, is proposed. In this method, STFT first employed to obtain velocity improve SNR without additional calculation. After that, SRT presented remove range migration (RM). Finally, (FT) conducted achieve in...
spectral decomposition is a powerful tool for analysis of seismic data. fourier transform determines the frequency contents of a signal. but for analysis of non-stationary signals, 1-d transform to frequency domain is not sufficient. in early years, transforming of seismic traces into time and frequency domain was done via windowed fourier transform, called a short time fourier transform (stft)...
تشخیص و طبقه بندی شناور های دریایی بر اساس نویز تشعشعی صوتی از آن ها از جمله ضرورت های سیستم های سوناری است. سال ها این کار در نیروهای نظامی جهان به توانایی ها و دقت اپراتور سونار وابسته بود. افزایش پیچیدگی های محیط زیر آب، ضرورت استفاده از فناوری های نوین و ایجاد سامانه هوشمندی سونار، بیش از پیش احساس می شود. غیرایستان بودن ماهیت نویز تشعشعی شناور های دریایی و وابستگی آن به کانال انتشار، متغیر...
Time-frequency representations provide a convenient method for analyzing signals whose frequency content changes with time, and speciically those signals with components that overlap in time and/or frequency. In this paper we suggest a technique for optimally concentrating components of a signal in the time-frequency plane via a particular choice of analysis window for the short-time Fourier tr...
In this study, short-time Fourier transform (STFT) and wavelet transform (WT) were used for spectral analysis of ophthalmic arterial Doppler signals. Using these spectral analysis methods, the variations in the shape of the Doppler spectra as a function of time were presented in the form of sonograms in order to obtain medical information. These sonograms were then used to compare the applied m...
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