Test & Measurement
 452 results found for Test & Measurement, displaying items 1 - 20

February 2010
Analyze Phase Noise In A Sampled PLL (Part 2)
Phase noise in sampled phase-locked loops (PLLs) can impact the performance of a wide range of commercial and military systems, including communications networks based on phase modulation. As shown last month in the first installment of this three-part series, modeling approaches may differ depending upon whether a PLL is a continuous-time or sampled system, with nonlinear approaches needed for th latter. In this second article installment, it may be...  — Peter Beeson

February 2010
USB Devices Simplify RF/Microwave Testing
Computer-controlled test equipment once evoked images of racks of instruments connected to a “technical” computer via the general-purpose interface bus (GPIB). While GPIB-controlled gear is still a staple of many automatic-test-equipment (ATE) applications, newer test interfaces, such as the Universal Serial Bus (USB), are quickly gaining ground for their ease of use and flexibility. In fact, the availability of a growing number of measurement functions...  — Jack Browne

February 2010
Handheld VNA Lowers Drift Errors With 0.01 dB/°C Stability
FIELD ENGINEERS who characterize or troubleshoot RF components for mission-critical communication systems have a new option in the N9923A FieldFox RF vector network analyzer (VNA). At 6.2 lbs., this full two-port VNA provides measurement stability of 0.01 dB/°C. It spans 2 to 4 or 6 GHz. The N9923A offers more than 42 dB directivity with a typical dynamic range of 100 dB. The VNA provides 0.01 dBm RMS trace noise. It allows operators to simultaneously measure...  — Nancy Friedrich

January 2010
Nonlinear S-Parameters And SDR Impact Test And Measurement Equipment
Test and measurement is crucial for research and development through production. As a result, test-equipment manufacturers have had to speed the evolution of their instruments to keep up with rapidly changing wireless-communications standards. They also are relying more on software—either through links to electronic-design-automation (EDA) tools or via software-designed-radio (SDR) architectures. At the same time, test equipment is increasingly being ...  — Nancy Friedrich

January 2010
Spectrum Analyzers Open Windows On An RF World
Spectrum analyzers have changed drastically in recent years, due largely to the use of digital components. Once predominately based on a superheterodyne receiver architecture to downconvert input signals to intermediate-frequency (IF) signals that were then filtered and processed, newer spectrum analyzers are just as likely to be called “signal analyzers” and employ sampling techniques with a high-speed analog-to-digital converter (ADC). As...  — Jack Browne

January 2010
System Performs FM Radio Drive Testing
Commercial automotive AM/ FM radios must perform dependably under a variety of operating conditions. Because designers of these radios employ digital-signal-processing (DSP) algorithms to overcome the effects of reflections, signal multipath, and fading, they often spend weeks in the field analyzing the effects of different signal conditions. A more practical and less time-consuming solution is the use of actual recorded radio signals to simulate the...  — David Brace , et al.

January 2010
Analyze Phase Noise In A Sampled PLL, Part 1
Phase locked loops (PLLs) have been used for years to stabilize signal sources such as oscillators. In the past, loop bandwidths tended to be small compared to the sampling frequency, but with modern communications systems, requirements for faster switching times mean that this is no longer the case. Narrow-bandwidth PLLs can be effectively modeled and simulated by means of linear analysis, but these same approaches fall short for ...  — Peter Beeson

January 2010
Broadband VNAs View Nonlinear Behavior
Last year, the new Vectorstar microwaVe Vector network anaLyzers (Vnas) from Anritsu created a stir in the industry, with their powerful combination of high accuracy, fast measurement speed, and broad bandwidths (see Microwaves & RF, January 2009 Cover Feature). Since then, the industry’s appetite for nonlinear S-parameter measurements has grown. To satisfy that need, the firm has made its MS4640A family of VNAs...  — Steve Reyes

January 2010
Portable Testers Provide Flexibility
Portable RF/microwave test equipment may fall short in performance compared to their benchtop counterparts, but they provide other benefits, including adding test power in places that larger gear won’t go. This survey samples available portable high-frequency test instruments and how they are being used in traditional and some novel applications. Perhaps one of the most popular of portable RF/microwave test instruments is the spectrum...  — Jack Browne

January 2010
LTE Challenges Test Gear Suppliers
Untitled Document Long Term Evolution (LTE) wireless networks pose some challenges for test equipment suppliers. The LTE air interface, as defined by Release 8 of the Third Generation Partnership...  — Jack Browne

January 2010
Signal Generator Ranges To 20 GHz
Testing microwave components usually calls for a highquality signal source. The model HMC-T2100 synthesized signal generator from Hittite Microwave Corp. provides reliable, accurate test signals from 10 MHz to 20 GHz. It can be used for CW, sweptfrequency, and swept-power testing using its front-panel controls or a choice of programming interfaces. The HMC-T2100 signal generator (...  — Jack Browne

December 2009
VME/VXS Cards Capture Agile Signals
Signal capture is an essential part of many military and intelligence systems. With suspect signals lurking within increasingly dense signal environments, high-speed digitizers are needed for reliable signal acquisition and processing. Fortunately, the Acqiris models SVM3500 and SVM4800 VME/VXS format digitizers from Agilent Technologies provide the signalprocessing firepower needed to grab as many...  — Jack Browne

November 2009
VNAs Characterize Supercomputer Cable Assemblies
 — Mike Resso

November 2009
Configuring Software For WiMAX Testing
Manufacturing test requirements for Wi- MAX and wirelesslocal- area-net-work (WLAN) devices must be comprehensive yet flexible. Traditional test solutions consist of three independent elements: chipset control software from the integrated-circuit (IC) vendor, test equipment, and the test software (or test executive), which allows the execution of an automated test plan. To save test engineers time and effort, test equipment vendors have combined...  — Robin Irwin

November 2009
Measure Group Delay Without Direct LO Access
Group delay that is well controlled in frequency-conversion components, such as mixers, is essential for many high-speed, highfrequency systems. It is critical for achieving low bit-error-rate (BER) performance in wireless and satellite communications receivers and for high target resolution in phased-array radar systems. The typical approach for measuring group delay requires access to the converter’s local oscillator (LO) signal. However, the LO is often...  — Gregory M. Bonaguide

November 2009
Economy Analyzers Extend To 7.5 GHz
Signal analysis need not be expensive, as evidenced by the new CXA economy analyzers from Agilent Technologies. With two models offering frequency coverage of 9 kHz to 3.0 GHz (model N9000A-503) and 9 kHz to 7.5 GHz (model N9000A-507) for under $17,000, the CXA signal analyzers don’t scrimp on performance. They can be upgraded via software options for phase-noise, noise-figure, and vectorsignal- ...  — Jack Browne

November 2009
Implantable Microsystem Records Neural Activity
To both understand neural functions and realize practical neural prostheses, most experts have concentrated on high-density arrays of silicon-based microelectrodes for recording neural activity in the central nervous system using a single channel. Recently, an implantable wireless microsystem that can simultaneously record neural activity on 64 channels was developed by Amir M. Sodagar, Gayatri E. Perlin, Ying Yao, Khalil Najafi, and Kensall D. Wise from the...  — Nancy Friedrich

November 2009
VNA Test Sets Measure 30 µs/point
With the low-end frequency of the MN469xB VectorStar 4-port test sets extended, these microwave multiport vector-network-analyzer (VNA) solutions can measure down to 70 kHz. They combine DC coverage and the wide-dynamic-range time-domain capability of a VNA, which makes them well suited for digital engineers who need to conduct signal-integrity measurements on passive, high-speed balanced transmission lines and connections. Two models are available in the MN469xB series....  — Nancy Friedrich

October 2009
Analyzers Scrutinize Signals To 26.5 GHz
Microwave signal analysis once brought to mind a slow-sweeping spectrum analyzer with unsteady cathode- ray-tube (CRT) screen to display signal traces barely above the noise floor. By leveraging performance advancements in semiconductors, digital signal processing, and analog components, however, Agilent Technologies has given rise to its PXA series of high-performance signal analyzers that keep the noise floor low and signal levels high enough...  — Jack Browne

October 2009
Cardiograph Extracts Time-Domain Heart Signals
PREVIOUS RESEARCH TACKLED the extraction of electro-cardiograph (ECG) –like waveform signals from a microwave-cardiograph (MCG). Those signals were analyzed in both the frequency and time domains to obtain heart-motion features. Recently, this research evolved to focus on the extraction mechanism and the analysis of the captured MCG graphs, thanks to the efforts of Jun Zheng and Yong Huang from East China Normal University together with Jian Qian from Nanjing...  — Nancy Friedrich





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