RF Test And Measurement Featured Articles

51. Quickly Evaluate High Performance Oscillators With A Phase Noise Analyzer 12/4/2017

    The process of evaluating the performance of ultra-low-phase noise oscillators requires phase noise test systems with lower measurement times, lower noise floor capabilities, and high reliability and repeatability of test data.

52. A Comparison Of Measurement Uncertainty In Vector Network Analyzers And Time Domain Reflectometers 5/28/2010
    Measurement uncertainty has a direct impact on the reliability of test instruments. To determine if there is a quantifiable difference in measurement uncertainty between the TDR and VNA, W. L. Gore & Associates performed a series of experiments, initially testing six cable assemblies in controlled conditions on each instrument. The instruments’ measurement uncertain under best-case scenario was evaulated using the highest-performing assembly. To ensure TDR/VNA test parity, the VNA’s performance was evaluated using a s11 one-port reflection method as well as the more traditional s21 two-port transmission method.
53. Introduction To Fixed WiMAX Measurements 11/2/2009
    As the deployment of WiMAX devices continues to increase, test engineers face an increasing challenge to reduce test costs. Thus, automated test systems used in either design validation testing or production testing must be designed to perform fast, accurate and repeatable WiMAX measurements. This article is aimed at the goal of equipping test engineers to understand the types of measurements typically required for characterization of Fixed WiMAX (IEEE 802.16-2004) devices. By National Instruments
54. Phase Coherent Multi-Channel RF Synthesis 9/23/2009

    Multi-channel synthesis applications require specific performance parameters that are often overlooked with the design of single channel synthesizer systems. Performance specifications for multi-channel synthesis applications typically require channel to channel, short and long term phase coherence that is not possible with phase-locking an N-number of single channel synthesizers together. This configuration only creates a long term phase-lock ‘average’ between the outputs. Each individual synthesizer also contributes to the short term stability of this system, which is problematic with traditional phase locked synthesizers. By Jason Breitbarth and Joe Koebel, Holzworth Instrumentation

55. Configuring Phase Coherent RF Measurement Systems: From MIMO To Beamforming 8/19/2009
    Ever since the first radio waves were transmitted, engineers have continually sought new ways to utilized electromagnetic microwave signals. While RF signals have since been used for a wide variety of applications, two specific applications that utilize one common technology are wireless communications and radar. This article explains the technical requirements to configure a phase coherent RF generation or acquisition system. In addition, a step-by-step process to calibrate the phase delay between multiple RF analyzers to achieve the best possible performance is presented. By National Instruments Corporation
56. Computational Magic And The EMC Engineer 6/10/2009
    In decades past, the EMC engineer had three basic methods for evaluating EM phenomenon: Maxwell’s Equations, circuit models, and fieldwork. The development of electromagnetic computational methods now provides us with another tool. In its current state of development, however, computational tools will not completely replace any of the methods above. Computer modeling of EM phenomenon in three dimensions requires a host of assumptions that make computational modeling a tricky business. To do it well, the engineer should not only have a working knowledge of Maxwell’s Equations, but should be familiar with the equally complex field of numerical analysis as well. By Dr. Glen Dash, Ampyx LLC
57. Shiver Me Timers! Using Spread Spectrum Clock Generators 5/21/2009
    Spread spectrum techniques are hardly new. The tale of their invention is oft-told, and usually begins with the filing of a 1942 patent by George Antheil and the actress Hedy Lamarr. The patent disclosed a method of frequency hopping used to immunize radio controlled torpedoes from jamming. In the last two decades, the technique has become a fixture in the communications industry because of its advantages in range, immunity, and security. The use of spread spectrum clock generation to reduce emissions in digital devices was first proposed in a paper presented at the 10th Annual Power Electronics Seminar at the Virginia Power Electronics Center in 1992...
58. TD-LTE Technology And Its Measurements 5/11/2009
    LTE, and particularly TD-LTE, brings new challenges to developers and to the vendors of design and test tools. New RF modulation schemes, MIMO antenna configurations, higher system bandwidths and capacity, and lower latency are just some of them. New measurement methods, including crossing the digital and RF domains, combined with a reduction in test point accessibility mean there’s a steep learning curve for both system and test developers. Successful technical introduction is a must, with analysts predicting between 30 and 80 million LTE subscribers and well over $100 billion in operator revenues within 5 years...
59. On-Chip Design For Better Noise Control 4/22/2009
    ICs can be designed to produce fewer emissions without compromising performance. In fact, good on-chip EMC design can go a long way towards eliminating other undesirable noise related problems, such as "ground bounce." And we are not talking about frequency-modulated clocks here. What we are talking about are techniques that work to lower emissions without changing the clock frequency.
60. Guest Column: Jitter - An Introduction 2/18/2009

    Jitter is a key concern for engineers developing high-speed components such as transmitters, receivers, and data channels. Discussing the subject matter of jitter completely would exceed the scale of this article. Instead, it provides a general introduction to jitter, causes and methods of jitter measurements, specifically BER and the eye diagram. It also talks about examples of standards concerning jitter-tolerance-measurements for serial high-speed components and takes a closer look at the test setup for a serial high-speed PCI express receiver.