Test & Measurement Channel - Leading Manufacturer News, Articles & Content

The Concept of Predistortion

The intention of this article is to provide a tool for the design of a predistorter, a component intended to correct unwanted nonlinear effects in power amplifiers. In order to come up with a design, a concept of predistortion is discussed. The conclus...
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...
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Application of GTEM Cells to Wireless Communication Transceiver Designs

The GTEM cell has been widely accepted as a sufficient tool in electromagnetic compatibility for both radiated susceptibility tests and radiated emission tests. In this article, the relationships among basic quantities such as input power, electric fie...
The gigahertz transverse electromagnetic mode (GTEM) cell was first proposed in 1987 1 and subsequently patented in 1989 by D. Konigstein and D. Hansen 2 as a high frequency variant of the transverse electromagnetic mode (TEM) cell, which is also known as the Crawford cell. 3 The GTEM cell...
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A Universal Oscillator Analysis Technique that Accurately Estimates Frequency and Output Power

During the last few decades, many different oscillator models and analysis techniques have been presented. From the negative impedance model, cavity type and DROs to the general feedback type, all oscillators have one common property. They are nonlinea...
Generally, an oscillator can be seen as a positive feedback system. It usually consists of an amplifier followed by a resonator, which is fed back to the amplifier input, as shown in Figure 1 . The amplifier task is to compensate for the losses in the resonator, and the...
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Conformal Subsections for Accurate EM Analysis

The fast fourier transform (FFT) approach to the method of moments (MoM) is well known for providing high accuracy, high dynamic range and robust electromagnetic (EM) analysis of planar circuits. The FFT consistently calculates the coupling between subsections to full numerical precision; no error is introduced by complex multi-dimensional...
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Design of a TRM Calibration Kit for the ZMA Coaxial Interface Using Ansoft HFSS

When new coaxial interfaces become available, it is important to validate their performance. The best way to do this is by using a calibration kit that eliminates the effects of adapters in the measurement. This article discusses the design and impleme...
One of the greatest challenges in characterizing new coaxial interfaces is to determine an accurate test configuration. When precision airlines are not available it is very difficult to obtain a true measurement of the device under test. It becomes necessary to design and implement calibration standards to eliminate the...
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RF Test Fixture Basics

When the RF test system and the device-under-test (DUT) both have coaxial connectors, hooking them together to make a measurement is easy. However, as radio-frequency integrated circuits (RFIC) have shrunk in size, traditional coaxial connectors are no longer useful. With the multitude of RF component sizes and shapes found...
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