In modern transmitting devices the digital predistortion technique is widely used for linearizing the power amplifier. There are many algorithms realizing predistortion technique with a different complexity and a stability of results. The several methods are described and compared. The orthogonal polynomials with memory were has proved to be simple enough with suitable results, so it was chosen...

MIMO-OFDM systems provide high spectral efficiency for wireless communication systems. However, they have a major drawback of high PAPR which results in inefficient use of a power amplifier and also improper detections. Now a days, in wireless communication systems, channel estimation is mandatory for higher data rates with low bit error rates. For reducing burden on system the channel estimati...

The distortion produced by a typical solid-state Class-B power amplifier is shown to consist of eight mechanisms, all of which may coexist and whose distortion products overlap to give a complex result. Methods for isolating each mechanism for study, and minimising its contribution, are given. If the avoidable distortions are designed out, Class-B amplifiers of unusually low distortion (Below 0...

A master oscillator power amplifier (MOPA) with variable amplifier gain lengths was built to demonstrate power enhancement of an alkali vapor laser. A small signal gain of 0.91 / cm for two different gain lengths was observed. For a 2 cm long amplifier gain length an amplification of 7.9 dB was observed.

The increased interest in vacuum tube audio amplifiers led to an increased interest in mathematical modelling of such kind of amplifiers. The main purpose of this paper is to develop a novel global numerical approach in calculation of the harmonic distortion (HD) and intermodulation distortion (IM) of vacuum-triode audio amplifiers, suitable for applications using brute-force of modern computer...

The existing UHF Satellite Communications (SATCOM) transponders used for military applications use efficient, saturated power amplifiers, which provide one earth-coverage antenna beam. The amplifier is dedicated to small frequency band and only handles a few carriers simultaneously. The communications capacity needed to support future military forces on the move will require satellite payload p...

We investigate the energy optimization (minimization) for amplified links. We show that using the using a well-established analytic nonlinear signal-to-noise ratio noise model that for a simple amplifier model there are very clear, fiber independent, amplifier gains which minimize the total energy requirement. With a generalized amplifier model we establish the spacing for the optimum power per...

In several reports issued previously, a theoretical analysis has been given for the steady-state operation of a vacuum-tube power amplifier with a complex load impedance* This theoretical work was checked experimentally with amplifiers operating in the steady state at low power levels. One application of an amplifier which sometimes must operate with a complex load impedance is in naval sonar e...

This paper reports the design, optimization, and test results of a mechanical amplifier coupled to an electromagnetic energy harvester to generate power from lowamplitude (±1 mm) and low-frequency (<5 Hz) vibrations in the presence of large static displacements. When coupled to a translational kinetic energy harvester, the amplifier boosts small vibration amplitudes by as much as 4x while accom...