Discussions on a form of a frequency spectrum of wind-driven sea waves just above the spectral maximum continue during the last three decades. In 1958 Phillips made a conjecture that wave breaking is the main mechanism responsible for the spectrum formation. That leads to the spectrum decay ∼ ω−5, where ω is the frequency of the waves. There is a contradiction between the numerous experimental ...

The intermodulation performance of a helix TWT was computed using a large-signal disc model with two, three and eight correlated carriers and also using the program IMAL which models a generalized nonlinearity described by its single carrier transfer characteristics. The results obtained by both methods showed good agreement. The inter-modulation performance of a TWT for both correlated and unc...

Variable frequency devices are widely used in many power systems. A current tracking based VFD is proposed in this paper. The output current is firstly fed back and compared with a standard sine wave, the difference of them is then used for a PI regulator to control the PWM signal, so as to change the output current accordingly to make it approach the standard sine wave. Simulation and experime...

Abstract  In this paper a new estimator for the measurement of the rms value of a noncoherent sampled sine-wave is proposed. The key feature of this estimator is that the sine-wave offset, a priori estimated, is removed from the sine-wave. A formula used to estimate the sinewave offset is also given in the paper. It has been proved by means of computer simulations and experimental results that...

Producing and manipulating the sine wave function is a common problem encountered by circuit designers. Sine wave circuits pose a significant design challenge because they represent a constantly controlled linear oscillator. Sine wave circuitry is required in a number of diverse areas, including audio testing, calibration equipment, transducer drives, power conditioning and automatic test equip...

If the sampled diffraction pattern due to a planar object is used to reconstruct the object pattern by backpropagation, the obtained pattern is no longer the same as the original. The effect of such sampling on the reconstruction is analyzed. The formulation uses the plane-wave expansion, and therefore the provided solution is exact for wave propagation in media where scalar wave propagation is...

A small-scale laboratory adaptive optics system using a Shack-Hartmann wave-front sensor (WFS) and a membrane deformable mirror (DM) has been built for robust image acquisition. In this study, an adaptive limited control technique is devised to maintain the long-term correction stability of the adaptive optics system. To prevent the waste of dynamic correction range for small residual wave-fron...

An advanced dynamic model for multisection semiconductor optical amplifiers is Presented. It accounts for the carrier and field distributions in the longitudinal direction as well as for the facet reflectivities. The model can handle arbitrary time-varying input signals and current modulations. Here the model is used to assess intermodulation distortion and crosstalk. First, cascaded amplifiers...

In this paper, hybrid modulation methods suitable for H-bridge MLI are discussed. The results of experimental work using dSPACE system only are presented for three phase five level cascaded type inverter. Different hybrid carrier PWM (Pulse Width Modulation) strategies using sinusoidal reference, third harmonic injection reference, 60 degree reference and stepped wave reference for the chosen i...