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Computationally efficient real-time digital predistortion architectures for envelope tracking power amplifiers
This paper presents and discusses two possible real-time digital predistortion (DPD) architectures suitable for envelope tracking (ET) power amplifiers (PAs) oriented at a final computationally efficient implementation in a field programmable gate array (FPGA) device. In ET systems, by using a shaping function is possible to modulate the supply voltage according to different criteria. One possibil
Digital predistortion of envelope-tracking power amplifiers under average power back-off and long-term average power efficiency for base-station applications
In many base-station applications, the load/usage fluctuates over time periods of hours to days, thereby varying the required transmit power by as much as 10 dB. It is desirable to maintain high efficiency and linearity in the power amplifier under these back-off conditions in order to achieve high long-term efficiency. This paper demonstrates a scalable digital predistortion (DPD) approach that c
New order selection technique using information criteria applied to SISO and MIMO systems predistortion
This paper presents a new order selection technique of matrix memory polynomial technique that models the nonlinearities of single-branch and multi-branch transmitters. The new criteria take into account the complexity of the model in addition to its mean-square error in the selection criteria. The quasi-convexity of the proposed criteria was proven in this work. By using this proposed Akaike info
Non-analytic at the origin, behavioral models for active or passive non-linearity
Most non-linear behavioral models of amplifiers are based on functions that are analytic at the origin and thus can be replaced by their Taylor series development around this point, e.g. polynomials of the input signal. Chebyshev Transforms can be used to compute the harmonic response of the model to a sine input signal. These responses are polynomials of the input signal amplitude. A second appli
High-performance digital predistortion test platform development for wideband power amplifiers
In this paper, a complete design procedure, together with robust system validation approaches, is presented for implementing a high-performance re-configurable digital predistortion (DPD) test platform for compensating for nonlinear distortion and memory effects induced by radio frequency (RF) power amplifiers (PAs) in the transmitters of modern wireless communication systems. This hardware and so
Ideal amplification of broadband signals
This paper describes a digital signal processing (DSP) method for achieving ?ideal? amplification, maximizing both the average output signal power and power-added-efficiency for any signal waveform and any power amplifier (PA) transfer characteristic. Detailed algorithms are described for optimally accomplishing peak reduction (PR), predistortion (PD) linearization, and integration of these DSP te
An L-band noise radar demonstrator for ground-based measurements of ground surface backscattering
The paper describes a radar demonstrator that was used to collect L-band range profiles of illuminated ground surface. The measurement results are to be used by the Institute of Geodesy and Cartography as the reference data for satellite image interpretation. The demonstrator is a software-defined noise radar composed of commercial-off-the-shelf elements. The paper conveys the theory of scattering
Special issue on power amplifier linearization
Modular Ka-band switch matrices using two RF MEMS technologies
This paper presents the design and measurement of two different switch matrix modules based on Radio Frequency Microelectromechanical System (RF MEMS) switches. The operational frequency range is between 25.5 GHz and 26.5 GHz for data links between a Geostationary Earth Orbit (GEO) relay satellite and Low Earth Orbit (LEO) satellites. The switch matrix implements a key functionality for tracking t
3D imaging by fast deconvolution algorithm in short-range UWB radar for concealed weapon detection
A fast imaging algorithm for real-time use in short-range (ultra-wideband) radar with synthetic or real-array aperture is proposed. The reflected field is presented here as a convolution of the target reflectivity and point spread function (PSF) of the imaging system. To obtain a focused 3D image, the proposed algorithm deconvolves the PSF out from the acquired data volume with high speed due to f