Subsystems and Systems
October 10, 2006
Defence and security authorities around the world are presently pursuing the idea of Network-centric Operations as the key to efficiently identifying and fighting potential threats. For defence applications this is well accepted, but now civil governmental organisations are also using this approach for security applications. The basic idea is...Read More
September 20, 2006
Today picoChip announced that its WiMAX solution is part of M/A-COM’s recently announced 4.9 GHz VIDA broadband solution for Public Safety Grade Applications. Read More
September 8, 2006
Current trends in modern wireless communications systems require advanced digital signals to handle high data throughput. The wider frequency bandwidth of a data-containing signal channel, along with sophisticated digital modulation, result in stringent signal-to-noise ratio (SNR) requirements to maintain affordable data loss (bit error rate (BER), packet/frame error rate...Read More
September 5, 2006
Tremendous changes are occurring in the area of wireless communications, so much so that the mobile phone of yesterday is rapidly turning into a sophisticated mobile device capable of more applications than PCs were capable of only a few years ago. For example, the data rates provided by the...Read More
In this article, two ultra-wideband (UWB) bow-tie antennas, designed for ground penetrating radar (GPR) applications, are characterized by both numerical analysis and experimental measurements. The geometry and the different materials of the feed and t...
August 7, 2006
In recent applications of telecommunications and remote sensing at radio, microwave and terahertz frequencies, the exploitation of ultra-wideband (UWB) antennas is growing steadily. 1 In subsurface prospecting, for example, they can provide higher imaging resolution and better target characterization. 2 The design and analysis of such high performance antennas...Read More
Directed-energy weapons remain more experimental than available.
December 1, 2003
The detonation by the United States of a nuclear warhead 30,000 feet above Johnston Atoll in July 1962 lit up the night sky above the Hawaiian Islands, 800 miles away. It also created a power surge that shut down the streetlights and phone system of Oahu as well as...Read More
Ultra-wideband (UWB) techniques are based on the generation of extremely short digital pulses in the sub-nanosecond range (1 to 1000 picoseconds). The technology is vastly different from classical radio transmission. The extremely short pulses are gene...
December 1, 2003
Baseband pulses are video or carrier-less pulses of very short duration. Their spectral content is concentrated primarily from zero frequency through the microwave region of the spectrum. This tutorial attempts to describe some of the vagaries of these pulses and their use in ground penetration radars and communications. Figure...Read More
November 1, 2003
In order to test high power amplifiers used in today's cellular base station equipment it is sometimes necessary to perform automated switching of the high power amplifiers without shutting down the system to make the RF connection. The high power RF signal must be diverted from the main signal...Read More
November 1, 2003
Additive white Gaussian noise (AWGN) has proven itself over the years as a simple yet extremely valuable tool in measurements ranging from BER and SINAD testing to wireless link emulation and the overall characterization of communications receiver performance. The unique characteristics of AWGN are becoming even more useful now...Read More
October 1, 2003
Determining cross-modulation interference is an important factor in the design of a code division multiple access (CDMA) mobile transceiver. The cross-modulation interference level directly affects the performance of the receiver's ability to overcome the spurious interferences, such as what the IS-98 1 calls single tone desensitization. A few papers...Read More