Instantaneous Frequency Measurement (IFM) devices are the essential parts of anyESM, ELINT, and RWR receiver. Analog IFMs have been used for several decades. However, thesedevices are bulky, complex and expensive. Nowadays, there is a great interest in developing a wideband, high dynamic range, and accurate Digital IFMs. One Digital IFM that has suitably reached allthese requirements is mono-bi...

A class of time-frequency distributions with complex-lag argument is proposed. It is based on the ambiguity domain representations of real and complex lag moment, combined to provide a cross-terms free representation for multicomponent signals. Furthermore, the distributions from the proposed class provide a more effective instantaneous frequency estimation for signals with fast varying phase f...

Length frequency data of the longtail tuna, Thunnus tonggol collected from October 2006 to September 2007 were analyzed for evaluation of the stock parameters. T. tonggol is mainly caught by gillnet method. Yearly tuna and tuna-like catches in Iran are of the order of 174,234 mt, close to 46% of which are longtail tuna. The VBG parameters for longtail tuna were: L∞ =133.72cm K=0.35 year−1.The l...

Periodicity is commonly found in many physical phenomena. This paper describes the notion of instantaneous frequency amplitude spectrum (IFAS) which originally developed in the context of time-frequency signal analysis. The IFAS provides better the harmonic structure representation of speech signal than the short time Fourier transform (STFT) amplitude spectrum. We define harmonicity measure as...

The electroencephalogram (EEG), used to noninvasively monitor brain activity, remains the most reliable tool in the diagnosis of neonatal seizures. Due to their nonstationary and multi-component nature, newborn EEG seizures are better represented in the joint time–frequency domain than in either the time domain or the frequency domain. Characterising newborn EEG seizure nonstationarities helps ...

With the rapid and ongoing developments in telecommunication and electronic warfare technology, faster and more flexible systems are in demand. Wideband signal processing is thus needed to implement such systems. Microwave photonics has been introduced as a tool for achieving such ultra broadband signal processing. Instantaneous Frequency Measurement (IFM) receivers play an important role in el...

Stages of run-up or run-down of rotating machinery are unstable random process. The methods of time-frequency analysis, such as short time Fourier transform, wavelet transform and so on, will be employed to analyze the relevant test signals. To obtain the laws of the instantaneous frequency of multi-component signals during the run-up or run-down periods, the method based on peak search is wide...

The modulated oscillation model provides physically meaningful representations of timevarying harmonic processes, and has been instrumental in the development of modern time-frequency algorithms, such as the synchrosqueezing transform. We here extend this concept to multivariate signals, in order to identify oscillations common to multiple data channels. This is achieved by introducing a multiv...

One of the main goals in ultrasonic Doppler blood flow measurement is the estimation of the mean velocity. The Doppler signal’s instantaneous frequency has traditionally been used to estimate the mean velocity. In this work, a non-uniform discrete time frequency distribution is proposed: the warped discrete Choi Williams distribution (WTFDCW). The proposed procedure estimates the instantaneous ...