ISSUE DATE: SEPTEMBER 2005  OPTIONS
Military Electronics

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September 2005 - In This Issue

[Cover Story]
Wideband Mixers Hit High Intercept Points
Mixers are essential to most communications systems. Traditionally, they are used to upconvert signal frequencies for transmission and downconvert received signals to lower intermediate frequencies (IFs) for signal processing. Although they are inherently nonlinear devices, communications systems designers try to extract as much linear, wide-dynamic-range performance from these components as possible. To help this cause, Synergy Microwave (Paterson, NJ) has developed two new twists...  — Jack Browne

[News]
Wireless Puts Down Medical Roots
Wireless-communications and other high-frequency technologies are increasingly revolutionizing the medical industry. The obvious applications for these technologies are the wireless local-area networks (WLANs) that are being installed in some medical centers. Of course, wireless communications also can be credited for keeping doctors "on call" for years. As the medical-technology field grows, however, new applications are being spawned almost daily. As a result, a host of semiconductor...  — Nancy Friedrich

[Design Features]
Synchronized Synthesizers Aid Multichannel Systems
Direct-digital-synthesis (DDS)-based synthesizers are primarily known as agile frequency sources with low phase noise and excellent spurious performance. In many applications, they offer significant advantages over phase-locked-loop (PLL) synthesis methods like sub-hertz frequency tuning resolution, phase offset, and output amplitude control. With multiple source channels and synchronization capability now built into a pair of commercial DDS products—the four-channel AD9959 (...  — David Brandon , et al.

[Design Features]
Tracking Transmitter Compliance Testing
Verifying the performance of a digital communications system was once easy. When entire networks were installed and owned by a single company, and the system worked, extensive testing of the subcomponents was unnecessary. But in this age of more complex networks, with components hailing from many different sources, proper compliance testing must ensure that system-level specifications are met when all components are connected. In particular, some new approaches can help evaluate transmitter...  — Greg Le Cheminant

[Design Features]
Building Wireless Sensor Networks
Wireless sensor networks (WSNs) offer great promise for information capture and processing in both commercial and military applications. Successful system design and deployment includes understanding RF channel characteristics, and the choice of modulation scheme on power consumption. Such factors ultimately determine the available range and data rate of a WSN, as well as cost and battery lifetime. The increasing miniaturization of RF devices and microelectromechanical systems...  — Roshdy Hafez , et al.

[Design Features]
Method Measures Device Power And Gain
Power measurements on RF transistors and RF integrated circuits (RF ICs) have grown in complexity as a function of the modulation formats used with these devices. One of the most important measures of high-power device performance is saturated power. Because the parameter is difficult to evaluate with CW techniques, it is often tested under pulsed conditions. The approach presented here eliminates some of the key drawbacks of the typical method employed to make these measurements. It does...  — Frédéric Fernez

[Product Technology]
Cable Company Doubles As Connector Supplier
Some firms are synonymous with particular product lines. Even the name of EZ Form Cable Corp. (Hamden, CT) suggests their long association with cable products. But this is a firm that also offers extensive lines of RF/microwave coaxial connectors, ranging from lower-frequency BNC and TNC connectors through high-power Type N connectors and high-frequency SMA connectors. These connectors, of course, can be supplied with the company's cables as standard- and custom-length cable assemblies, or...  — Jack Browne

[Product Technology]
Coax Cables Improve Receiver Performance
Coaxial cable assemblies provide the vital link between antennas and receivers for high-performance avionics systems. Unfortunately, the signal attenuation caused by these coaxial cable assemblies has historically resulted in a significant degradation in the overall installed system performance. This long-standing limitation has now been virtually eliminated due to the introduction of a new product from Times Microwave Systems (Wallingford, CT)—a Zero dB™ coaxial cable...  — Jack Browne

[Product Technology]
Ceramic Technology Yields Stable Resonators
Frequency stability is critical in many applications that can require tight spectral tolerances. For those components subject to frequency variations, Dielectric Laboratories (Cazenovia, NY) has developed a customizable ceramic process for resonant circuits, such as resonators, diplexers, and filters. Applicable for components from 500 MHz to >67 GHz, the process offers, for example, a 10-GHz resonator with typical temperature coefficient of frequency of –2.3 PPM/°C (1 MHz drift...  — Jack Browne

[Editorial]
Re-evaluating Base Closings
Defense base closings have been as much a part of recent military news as the war in Iraq. The Department of Defense (DoD) has proposed consolidating a total of 62 major domestic US military bases and over 770 smaller installations in order to save the US government $48.8 billion through the year 2025. The closings are also meant to make the armed services more efficient and agile. The impact of these base closings goes far beyond the present and future of our military forces,...  — Jack Browne