The conventional frequency diversity array (FDA) can generate arcsine form of continuous direction modulation (DM) waveforms which automatically scan the entire space range. However, single waveform and time varying phase FDA cannot meet requirements practical security communication application scenarios. Thus, a new transmit technique, called (TFDM), is proposed to improve azimuth security. In...

Time-frequency transforms represent a signal as a mixture of its time domain representation and its frequency domain representation. We present efficient algorithms for the quantum Zak transform and quantum Weyl-Heisenberg transform.

This invited paper – of a tutorial and review character – presents an overview of two classes of time-frequency signal representations. The first class, in which the signal arises linearly, deals with the windowed Fourier transform and its sampled version (also known as the Gabor transform) and the inverse of the latter: Gabor’s signal expansion. We will show how Gabor’s signal expansion and th...

This paper presents an overview of some of the trends which are shaping the directions of development in time and frequency metrology. The paper focusses on the characteristics of frequency sources, methods for comparing separated clocks/oscillators, and tecKques for distributing time and frequency signals.

Study of the additive Gaussian noise influence on time-frequency (TF) distributions is an important issue [Article 9.1]. However, in many practical applications, especially in communications, signals are disturbed by a kind of impulse noise. These noises are commonly modeled by heavy-tailed (long-tailed) probability density functions (pdfs) [6]. It is well known fact that the conventional TF di...

This paper presents a generalization of the concept of adapted filter to a frequency modulated signal. This generalization is inspired by the time-frequency representations theory. A new time-frequency representation is proposed, its more interesting properties are derived and are used to built tracking filters. The implementation of this class of filters is shortly described.