Several LUT-based pre-distortion schemes using Saleh’s model for compensation of RF non-linearity have been studied recently. In this paper we propose a novel parameter-based predistorter to enhance the power efficiency of mobile OFDM transmitters using solid-state power amplifiers (SSPA). Both the non-linearity and inverse of the non-linearity are estimated as memory-less polynomials using Lea...

The linearity of the CMOS is of major concern in the design of many analog circuits. In this paper the nonlinearity behavior of CMOS analog integrated circuits is investigated.The basic building block of analog integrated circuits such as differential amplifier with current mirror load have been chosen for harmonic distortion analysis.A mechanism to analyze the distortion of CMOS circuits in de...

Table 1. A comparison of valid tensors in the DTIs based on DWIs of different strategies of distortion correction. Our method provided the best result, while some other method may increase the number of ill-conditioned tensors (nonpositive definite). (a) (b) (c) (d) Figure 1. A comparison of distortion correction using different approaches. First Row: The simulated dataset; Second Row: The real...

Fourier based feature extraction is a common and powerful technique used in texture classification. In case of endoscopic imaging, often significant barrel-type distortions affect the feature extraction. Although images can be rectified using distortion correction techniques, in previous work feature extraction proved to suffer not just from geometric distortions, but also from effects within d...

Daniel E. Stevenson and Margaret M. Fleck Department of Computer Science, University of Iowa, Iowa City, IA 52242, USA [email protected], m [email protected] Abstract Images taken with wide-angle and inexpensive medium-angle lenses show substantial distortion, which will cause many computer vision applications to malfunction. Parametric calibration algorithms cannot handle the wide range of possi...

OBJECTIVE Preoperative magnetic resonance imaging (MRI), functional MRI, diffusion tensor MRI, magnetic resonance spectroscopy, and positron-emission tomographic scans may be aligned to intraoperative MRI to enhance visualization and navigation during image-guided neurosurgery. However, several effects (both machine- and patient-induced distortions) lead to significant geometric distortion of i...

Modern video-based endoscopes offer physicians a wide-angle field of view for minimally-invasive procedures. Unfortunately, inherent barrel distortion prevents accurate perception of range. This makes measurement and distance judgment difficult and causes difficulties in emerging applications, such as 3D medical-image registration. Such distortion also arises in other wide field-of-view camera ...

Second-harmonic control is implemented in a balanced common-emitter configuration to facilitate frequency-independent third-order intermodulation distortion cancellation. Moreover, this circuit configuration facilitates a simultaneous match for either power and linearity or noise and linearity. Experiments demonstrated an improvement of over 15 dB in the output third-order intercept point while...

the application of traditional nmo-correction techniques in the processing of seismic data may result in severe distortion. this distortion is observed as a decrease in frequency content (nmo stretch). this may be seen as the source of problems in the processing with stretch. in this paper, cnmo method is applied which doesn't have the `stretching effects' of conventional nmo correcti...

Abs&act-A linearity improvement technique employing passive resistors and current-steering MOS transistors as a variable resistance element is proposed to implement a low-distortion filter in CMOS technology. This proposed implementation relies on the linearity of the passive resistors and the tunability of the current-steering MOS transistors operating in the triode region to overcome the limi...