December 2008 Test Radio Receivers With Recorded Signals Channel impairments can be disruptive on RF-based communications devices. Impairments such as fading and multipath, which are often unpredictable, can hinder wireless communications. Because channel impairments are often unpredictable and not repeatable, many engineers face the challenge of supplying a prototype receiver with a reliable model of the real-world signal environment. Fortunately, by understanding the causes of these impairments through... — Dominique Fortin , et al. December 2008 Software/Scope Combination Scrutinizes Complex Waveforms Oscilloscopes and spectrum analyzers are sometimes found on the same test bench. Each brings its strengths and limitations, with a scope’s triggering capabilities ideal for time-domain analysis and a spectrum analyzer’s sweep functions well suited for spectral displays. But what if those capabilities were combined? The answer would be the SignalVu vector signal analysis software from Tektronix, which is... — Jack Browne November 20, 2008 Assess Quadrature-Demodulator Noise Figure Using Vector Signal Analysis In a direct-conversion signal chain, it is often difficult to accurately predict the noise-figure impact due to an in-phase/quadrature (IQ) demodulator. Typically, the noise figure is measured using a noise-figure meter. Yet those meters do not operate at low enough frequencies to capture representative noise data at baseband frequencies... — Eric Newman , et al. November 2008 Tester Exercises MIMO Receivers WWireless systems must often contend With limited range and interference. For that reason, multiple-input, multiple-output (MIMO) technology is being applied to many emerging wireless standards, including 802.11n WLAN, Mobile WiMAX Wave 2 and 3GPP Long-Term Evolution (LTE) systems. The improved performance of MIMO approaches brings with it increased complexity, and the challenge of testing the hardware using MIMO methods. Fortunately, the N5106A PXB MIMO Receiver Tester from... — Wilkie Yu November 2008 RMS Detector Reads 40-dB Range to 6 GHz Power control is vital to many modern wireless communications formats, including GSM/EDGE, CDMA, WiMAX, and Long Term Evolution (LTE) cellular systems. Of course, to control power, it is first necessary to detect it, and the LT5581 root-meansquare (RMS) power detector from Linear Technology (www.linear.com) is a fast-active integrated circuit (IC) with 40-dB dynamic range from 10 MHz to 6 GHz.... — Jack Browne November 2008 USB Power Sensor Checks 50-dB Range To 6 GHz Precision power measurements at RF/microwave frequencies once required a standalone power meter and the proper diode or thermistor sensor. But with a personal computer (PC) equipped with a Universal Serial Bus (USB) and the model PWR-6G+ USB power sensor from Mini-Circuits (minicircuits.com), power measurements can be made quickly and accurately over a level range of -30 to +20 dBm and across... — Jack Browne November 2008 USB Power Meter-Sensor Covers 10 MHz To 12.5 GHz THE MODEL LB559A PowerSensor+ power meter-sensor is a compact Universal-Serial-Bus (USB) powered solution for power measurements at frequencies from 10 MHz to 12.5 GHz. The measurement tool boasts a dynamic range of –55 to +20 dBm with total measurement error of only 1.95 percent. The instrument features “No Cal, No Zero” operation that eliminates the need for calibrating or zeroing the power meter-sensor before use for faster measurement ... — Nancy Friedrich October 2008 Measure The Range Of Sensor Networks Wireless sensor networks (WSNs) provide invaluable services with their short-range communications capabilities. But their limited operating power can impose restrictions on the maximum allowable distance between the sensors and the base station.1,2 Due to this limitation, direct communications between a sensor and its base station is not always possible, especially in a difficult radio environment with strong attenuation. To overcome this... — R.A. Abd-Alhameed , et al. October 2008 Measurement Procedure Compares Gilbert Micromixers CMOS Technology has emerged as a solid option for low-cost wireless HDMI integrated circuits (ICs) in the 60-GHz band. Recently, two W-Band receivers have been reported by Mehdi Khanpour, Keith W. Tang — Nancy Friedrich September 2008 Design A Scanning RSSI Receiver For WiMAX Measurements WiMAX broadband wireless technology offers the promise of untethered, highspeed Internet access in supported service areas. Based on the IEEE 802.16 standard, WiMAX is specified for use in a wide range of frequencies through 66 GHz, with a variety of operational profiles differentiated by frequency band, channel bandwidth, and duplexing mode.1-3 WiMAX has been developed rapidly from inception to deployment. According to a recent (January 2008)... — Zhengbo Jiang , et al. September 2008 Achieving Amplitude Accuracy In Modern Spectrum Analyzers Spectrum analyzers are among the most versatile of RF/microwave measurement tools, with signal power among the most common measurement made with the instruments. Traditionally, the combination of a power meter and power sensor has been the measurement tool of choice for its well-characterized traceability path back to reference standards at national standards laboratories. But modern spectrum analyzers have made dramatic improvements in amplitude... — Joe Gorin September 2008 Multipurpose Impedance Tuner Is Portable Solution Impedance tuners are unique but vital tools that can provide invaluable insight into the behavior of active component designs, such as amplifiers, as well as passive circuits, such as antennas. Precision impedance tuners are based on sliding mechanical probes, with the impedance shown to a component or device under test determined by the position of the sliding probes. While such impedance tuners can represent a major capital investment for many ... — Jack Browne August 2008 Use Pulse I-V Testing To Characterize RF Devices Pulsed current-voltage (I-V) testing is becoming an invaluable method for evaluating the performance and reliability of semiconductor devices. The measurement approach is relatively cost effective and avoids the negative effects of self-heating and transient trapped charges, which can result in misleading test results. And pulsed I-V testing provides the accurate device data needed for improved computeraided- engineering (CAE) software models. ... — Pete Hulbert August 2008 Design An X-Band Vivaldi Antenna, Part 2 Vivaldi antennas can provide excellent directional propagation at microwave frequencies. As introduced in Part 1 of this article (July Microwaves & RF), the Vivaldi antenna can be a simple design based on a tapered-slot-antenna (TSA) architecture. This concluding installment in this two-part article will compare measurements of a designed and fabricated X-band antenna with simulations from the Advanced Design System (ADS) software from Agilent ... — Dr. J.S. Mandeep , et al. August 2008 Analyze Antenna Approaches for LTE Wireless Systems Multiple-input, multiple- output (MIMO) spatial-diversity antenna configurations are specified for emerging 3GPP Long- Term Evolution (LTE) mobile communications systems. In reality, LTE systems specify three types of antenna techniques: MIMO, beamforming, and diversity approaches. The three techniques are considered essential for improving signal robustness and achieving LTE system capacity. Understanding how the different antenna techniques work... — Moray Rumney , et al. August 2008 Rohde & Schwarz Celebrates 75 Years Germany has long been associated with the type of precision engineering that has produced high-quality cameras, fast automobiles, and even the Autobahn roadway to accommodate those higher driving speeds. But this proud country is also home to one of the leading and most innovative test-andmeasurement companies in the world: Rohde & Schwarz GmbH. From its humble beginnings, the firm has grown through the years to now achieve its 75th anniversary, a... — Ulrich L. Rohde August 2008 Test Software Simplifies Phase, Power Measurements Microwave measurements can be made easier with the help of the right software. This was the thinking behind the introduction of two software tools by Anritsu Co. (www.us.anritsu.com) designed to assist with phase-noise and power measurements when using the firm’s MS271xB family of economy spectrum analyzers and its ML2490A series of power meters, respectively. The programs run on a personal... — Jack Browne August 2008 Software Tools Simplify GPS Testing Global Positioning System (GPS) receivers have been guiding travelers for some time, and now they are guiding drivers of many new cars and even pedestrians by means of embedded circuits in cellular telephones. Of course, with this rapid spread of GPS receivers comes a corresponding need for efficient testing of both stand-alone GPS receivers and units embedded into other devices. For that purpose, the NI GPS Toolkit for Labview from National Instruments (... — Jack Browne August 2008 170-MHz Signal Generator Fits Benchtop BY LEVERAGING an internal temperature-controlled crystal oscillator (TCXO), a direct-digital-synthesized (DDS) signal generator provides accuracy of better than +/-2 ppm. Model 2918A contains two synchronized 170-MHz DDS sources that can be individually set to any value between 0.1 Hz and 170 MHz with a resolution of 0.1 Hz. The phase between the channels can be controlled with 14-b resolution. The standard output level is +4 dBm with 10 b programming range.... — Nancy Friedrich August 7, 2008 UWB Test Solution Claimed To Be Industry First Taiwanese provider of wireless test-system solutions, LitePoint Corporation, has developed three new systems for testing wireless standards. The new IQnxn Plus system provides a multi-stream signal — Paul Whytock |
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