We have investigated the modulation of the optical field transmitted through a colloid of polystyrene spheres by a narrow quasi-cw ultrasound beam. Measurements of the scale dependence of the heterodyne modulation signal at the acoustic frequency are obtained for samples that are up to 140 scattering lengths thick. A calculation of the modulation signal predicts the possibility of tomographic i...

This contribution deals with asynchronous noncoherent recognition of modulation types. The main aim is to recognize OFDM modulation method from some other single-carrier analog and digital modulation types in the presence of AWGN noise. The described solution of recognizer uses key features of the received signal. The signal amplitude is observed at the output of the quadrature intermediate-fre...

When the short-time Fourier transform (STFT) of an audio signal is arbitrarily modified, it no longer truly represents a time-domain signal. Classically, the accepted solution to obtain a time-domain signal from a modified STFT (MSTFT) is to invert the MSTFT to a time-domain signal that has an STFT that is closest to the MSTFT in a least squares sense. This is also the approach currently taken ...

Sigma delta modulation M has become a widespread method of analogue to digital conversion however its operation has not been completely de ned The majority of the analysis carried out on the circuit has been from a linear standpoint with non linear analysis hinting at hidden complexities in the modulator s operation The sigma delta modulator itself is a non linear system consisting as it does o...

If weakly interacting massive.particles (WIMPS) are the dark matter in the galactic halo, they may be detected in low background ionization detectors now operating or with low temperature devices under development. In detecting WIMPS of low msss or WIMPS with spin-dependent nuclear interactions (e.g., photinos), a principal technical difficulty appears to be achieving very low thresholds (5 O(k...

While Σ∆M techniques [l, 2] are applied widely in analog conversion sub-systems, both analog-to-digital (ADC) and digital-to-analog (DAC) converters. these methods have enjoyed much less exposure in the broader application domain, where flexible and configurable solutions, traditionally supplied via a software DSP (soft-DSP), are required. And this limited level of exposure is easy to understan...

In many questions of signal processing, it is important to use the concepts of instantaneous amplitude or phase of signals. This is especially the case in communication systems with amplitude or frequency modulation. These concepts are often introduced empirically. However, it is well known that the correct approach for this purpose is to use the concept of analytic signal. Starting from this p...

In radio communications, modulation can be described as the process of conveying a message signal by superimposing an information bearing signal onto a carrier signal by varying the signal characteristic [31–33]. Modulation is the process of changing a higher frequency signal in proportion to a lower frequency one or vise versa. The higher frequency signal is referred to as the carrier signal a...

Abstract With the continuous research and development of global positioning system in various countries, requirements for accuracy efficiency GPS signals are getting higher higher. To improve performance signal modulation, this focuses on BPSK modulation BOC introduces basic principles practical uses two signals. Based disadvantage weak anti-noise modulated high ambiguity signal, algorithms sig...

We study variable node degree distributions resulting from a linear programming approach for designing a lowdensity parity-check (LDPC) code optimized for an irregular modulation alphabet. We opt for an irregular LDPC code and make use of the irregularities of the channel in the sense of different modulation classes originating especially from different distances in a hierarchical modulation si...