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Industry News

New Types of Millimeter-wave Noise Sources

Used for remote sensing in various applications and environments, microwave and millimeter-wave radiometers (RM) require frequent calibration. Microwave radiometers measure noise temperature using a suitable antenna which is designed to match a scene of interest, as shown in Figure 1 . In a technical sense, if the antenna's main...
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A Cellular Band Power Amplifier/Duplexer Module

Wireless communications handsets are increasing in functionality through the addition of features such as GPS, color displays and PDA functions. At the same time the handset is maintaining a roughly constant price and size target. Because of this trend, handset manufacturers are requiring higher levels of integration from component...
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An Adaptive Feedforward Amplifier for WCDMA Base Stations Using Imperfect Signal Cancellation

This article describes a new adaptive feedforward amplifier for a WCDMA system using an imperfect signal cancellation. Due to the complicated signal statistics, the distortion generated by the error amplifier is significantly reduced by an imperfect si...
As wireless systems evolve from second- to third- or fourth-generation, the linearity, efficiency and bandwidth requirements for power amplifiers become more stringent. Many techniques, including feedforward, envelope feedback and manifold types of predistorters, have been employed to effectively satisfy these performance requirements and to reduce the production costs for...
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Design of a Predistorter Controlling Individual Orders of Intermodulation Using a New Harmonic Generator

A new type of predistortion linearizer is presented which uses individual orders of intermodulation to linearize a power amplifier. This new predistortion linearizer has two harmonic generators, each consisting of four diodes biased independently. Sinc...
In multi-carrier power amplifiers, a feedforward technique is generally adopted due to its extremely linear and broadband characteristics. 1 However, the feedforward technique requires large circuits and is expensive because of its complexity. It uses two cancellation paths, and delay lines are inserted in each path to adjust the...
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A Novel Adaptive Feedforward Amplifier Using an Analog Controller

A novel adaptive design for a feedforward amplifier linearizer with an analog controller is proposed in this article. Compared with previous adaptive linearizing methods, this new design does not require any pilot signal or intentional signal distortio...
For the third-generation (3G) mobile radio standards, a very high linearity transmitter that can support high crest factor signals is necessary. High linearity and high efficiency are critical issues in amplifier design. In fact, as the power amplifier operates close to the saturation region where both high efficiency and...
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Specification and Measurement of Local Oscillator Noise in Integrated Circuit Base Station Mixers

Residual phase noise from local oscillators can be degraded by additive noise of on-chip local oscillator (LO) drivers/buffers in integrated circuit mixers. Reciprocal mixing of strong RF signals with the LO noise degrades the receiver sensitivity. Spe...
Cellular base station receivers work in the presence of high level blockers/interferers while being required to sense weak signals of interest at the antenna. The interferers are usually rejected by filters but only at an intermediate frequency (IF) after the first down conversion. The LNA and mixer preceding the...
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A Voltage-controlled PIN Diode Attenuator Using an Accurate PIN Diode Model

This article presents a voltage-controlled PIN diode attenuator using an accurate PIN diode model that can precisely simulate the attenuation characteristics. After carefully investigating the problems with conventional PIN diode models, an accurate PI...
PIN diodes have been widely used in a variety of microwave and RF applications, including antenna switches, phase shifters and attenuators. PIN diode attenuators are used extensively in automatic gain control (AGC) and RF leveling applications. Most PIN diode attenuators control the attenuation characteristics through the forward bias current....
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Turnkey Network Opens the Door for Alcatel in Nigeria

In order to unlock the vast potential of the African market, Globacom, the second national carrier of Nigeria, has awarded Alcatel a major global frame contract, with an initial order of 675 M, for the supply of a nation-wide turnkey mobile and fixed telecommunications network, including microwave routes. The...
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Siemens and Tele2 in Russian Federation

Marrying the skills of two leading companies, the Sweden-based telecom operator Tele2 AB has awarded Siemens Information and Communication Mobile Group (Siemens mobile) the contract to build its GSM 1800 network throughout the Russian Federation. As per the agreement, Siemens mobile will provide the switching network, radio base stations...
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Dual-band WLAN Pioneer Crosses Frontiers

Demonstrating that technical development knows no boundaries, Synad, the fabless WLAN System-on-Chip company, has begun an international expansion programme with the opening of new offices in Asia, Europe and the US. The company has moved into a new 10,000 ft2 headquarters and engineering facility in Reading, UK, which will...
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