Subsystems and Systems

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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...

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...

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...

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...

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...

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...

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...

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...

This article continues the trend of previous publications, 1,2 to simplify the prediction of RF performance of systems designed for wireless digital communications. The first shows the correlation between sidelobes and intermodulation (IM) products. Sidelobes are the result of the spectrum re-growth when a digitally modulated signal is applied...

A new Radio On a Chip (ROC) has been developed to meet the needs of the emerging short range and low data rate wireless link market. The HRF-ROC093XC ROC has been introduced for wireless, digital data applications in a broad arena of industries. This radio operates in the 902...