Cognitive radios are expected to perform spectrum sensing and communication in the frequency range of tens of megahertz to about 10 GHz. As such, they pose tough architecture and circuit design problems. This paper deals with issues such as broadband, low-noise amplification, multidecade carrier frequency synthesis, and spectrum sensing. The paper also describes the effect of nonlinearity and l...

extremely low frequency (elf) and radio frequency (rf) electromagnetic field may affect biological systems by raising generation free radicals by decline activities of glutathione peroxidase dismutase or increase in the lifetime of free radicals with inhibited pretreatment of cells antioxidant like that alpha tocopherol. elf and  rf electromagnetic  field maycan damaged dna  with raising level ...

In DELPHI Volume IV, Chapter 3 (1993) it was argued that by making assumptions about the propagation behavior of a synthesized (plane) wave through a weathered layer it is possible to consider the weathered layer effects at the source and receiver side separately. The fast weathered layer distortion to the (plane) wave front at the source side is largely restored during propagation through the ...

Cognitive radio (CR) is designed to detect available frequency bands/channels. Spectrum sensing plays a critical role in CR with energy detection being the most common method. In our paper, we implement energy detection using GNU Radio and USRP boards as a test-bed. Specifically, energy detection is performed by using blocks in GNU Radio Companion (GRC) to calculate the energy of a present sign...

We demonstrate a practical concept to extend the performance at the air interface of RFID Proximity readers using integrated reader chips. Our solution consists of an external, discrete circuit and we consider the transmit path as well as the receive path. We discuss important aspects for design and evaluate the quality improvement for a specific reader in some relevant characterization measure...

This document treats the crosstalk between parallel conductors. The conductors can represent either conductors in a multiconductor cable or traces on a printed circuit board (PCB). An analysis method based on a lumped circuit equivalent for the problem as well as a method to calculate the per unit length parameters are presented. The computed results are validated by comparison with measurement...