In this paper we present a multiresolution-based method for period determination that is able to deal with unevenly sampled data. This method allows us to detect superimposed periodic signals with lower signal-to-noise ratios than in classical methods. This multiresolution-based method is a generalization of the wavelet-based method for period detection that is unable to deal with unevenly samp...

The discrete time–frequency matched filter should replicate the continuous time–frequency matched filter. But the methods differ. To avoid aliasing the discrete method transforms the real-valued signal to the complex-valued analytic signal. The theory for the time–frequency matched filter does not consider the discrete case using the analytic signal. We find that the performance of the matched ...

Introduction: In magnetic resonance imaging a tradeoff exists between resolution and the signal to noise ratio (SNR). With any imaging protocol, different fractions of the available scan time could be used to acquire data at higher spatial frequencies (achieving higher resolution) and to perform signal averaging (obtaining greater SNR). A potential way to establish the optimal balance between r...

The Bayesian time-frequency detector operating on spectrogram of non stationary signals is studied. As direct evaluation of the likelihood ratio is impossible, an a priori user parameter called focus is introduced. It is defined as a local time-frequency signal to noise ratio at which the detection is tuned to be optimal. Leading to a unique detection threshold, the parameter introduced is equi...

Self-Mixing (SM) is a promising technique for sensing vibration, distance, velocity etc. To retrieve accurate metric measurements from an acquired SM signal, it is necessary to correctly detect all interferometric fringes. Traditionally, SM fringes are detected by a derivative based threshold (DBT) scheme. However, such a scheme gives correct results only for SM signals with high signalto-noise...

The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite will be launched in April of 2005, and will make continuous measurements of the Earth's atmosphere for the following three years. Retrieving the spatial and optical properties of clouds and aerosols from the CALIPSO lidar backscatter data will be confronted by a number of difficulties that are not faced i...

Structural health monitoring of historical structures typically involves collecting continuous vibration data with very low signal-to-noise ratios (SNR). Fourier-based standard spectral analysis techniques are not appropriate to analyze such data, because low SNR can cause large errors in spectral analysis, particularly when they involve spectral ratios. This is particularly true for historical...

In this paper we study the effects of the prefilter on the jitter of a data synchronizer. We will see the prefilter as the parameter that can influence the curve of the output jitter versus input noise. We will show as the prefilter is beneficial for low signal to noise ratios (SNR) and prejudicial for high SNR. For low noise quantities the synchronizer operates in the linear mode but the incre...

Word familiarity effects on lexical decision times and recognition scores were investigated for two sets of 100 spoken Japanese words whose familiarity ratings ranged from middle (4.0) to high (7.0) taken from a recently-developed word familiarity database containing about 80,000 Japanese words. The results showed that the higher the word familiarity rating is, the shorter the reaction time is,...