Microwave Journal articles from April 1998

Microwave Journal archives from April 1998

A control system for a feedforward amplifier.
April 1, 1998... Modern wireless communication systems are placing new demands on power amplifiers. Conventional cellular systems have used frequency modulation, a constant-envelope form of modulation. As such, it has been feasible to use high efficiency class C...

Racal publicises noncooperative bistatic radar programme. (Racal Radar Defence Systems)
April 1, 1998... UK contractor Racal Radar Defence Systems (RRDS) has published the first details of its noncooperative bistatic radar technology validation programme. Conceived to provide a covert passive radar-plotting capability for military applications, the...

Effects of matching on RF power amplifier efficiency and output power. (Radio frequency power amplifiers)
April 1, 1998... The most popular methods for designing RF PAs utilize load-pull techniques in different sophistication levels, techniques based on load-line theory and techniques based on nonlinear simulation. By far, the load-pull design techniques are still...

Cellular mobile radio communication channels in view of smart antenna systems.
April 1, 1998... The key role of multi-antennas at cellular mobile radio communications base stations is to sample, at different points in space, the waveforms propagating from users who are accessing the same communication channel. The effectiveness of spatial...

Sensitivity improvements and associated benefits of tower-top amplifiers. (part 2)
April 1, 1998... Wireless telephony uses either traditional analog or newer digital protocols for signal transmission. Analog systems, such as the Advanced Mobile Phone Service (AMPS) and the Total Access Communication System, use frequency-division multiple...

Design of a wideband, high dynamic range downconverter used in smart antenna applications.
April 1, 1998... The SAA system replaces a cellular provider's existing passive antenna array with a system that maximizes each channel's signal-to-noise ratio, reducing signal fading and dropped calls. The equipment rack houses digital signal processors, RF...

A 50 W solid-state C-band amplifier for outdoor use.(Cover Story)
April 1, 1998... Satellite communications systems are expanding at an unprecedented rate and service providers require increasing numbers of satellite uplink stations to satisfy their customers' needs. At the same time, cost control becomes a critical concern...

An RF distribution amplifier. (radio frequency)
April 1, 1998... The task of delivering a centralized reference signal to a number of different equipment stations without degrading the signal or creating crosstalk can be difficult, particularly when up to 100 locations require this signal. This situation is...

An OXCO with Rubidum oscillator performance. (oven-controlled crystal oscillators)
April 1, 1998... Precision crystal oscillators are widely used in systems for navigation, such as Global Positioning System (GPS) and cellular telephone applications. In many ways, the crystal oscillator is the cornerstone in determining critical performance such...

A low cost DC to 500 MHz logarithmic amplifier.
April 1, 1998... Logarithmic amplifiers are key components in a wide range of RF system applications. By virtue of its DC to 500 MHz frequency range and 92 dB dynamic range, the model AD8307 logarithmic amplifier can be used to measure signal strength directly at...

A 900 MHz single-supply GaAs power amplifier IC. (integrated circuit power amplifier; gallium-arsenide)
April 1, 1998... The current trend toward making cellular telephones smaller, lighter and more efficient continues to place high demands on component manufacturers to follow suit. Global System for Mobile communications (GSM), the largest segment of the cellular...