Conformity Magazine - October 2007 - (Page 43)

T raditional spectrum analyzers are scalar measurement devices, where the primary display is a scalar value (signal amplitude) plotted versus frequency. The most common measurements are signal power and frequency of spectral components such as harmonics, intermodulation and spurious. The power versus frequency values can be integrated or corrected for resolution bandwidth (RBW) to yield noise power (and phase noise), band power, adjacent channel power, and occupied bandwidth. Spectrum analyzers have also been frequently adapted to measure time domain or modulation domain characteristics. While traditional spectrum analyzers have many uses and benefits, today’s communications systems and MIL-STD applications require modern spectrum analyzers with their higher accuracy, performance and speed, as well as increased functionality. One area where modern spectrum analyzers are especially helpful is in electromagnetic interference (EMI) testing – a critical part of any product lifecycle. EMI measurements (e.g., pre-compliance and full-compliance testing) are made after a product’s completion to evaluate whether or not its EM emissions are within specified limits. In pre-compliance testing, the main goal is to determine whether or not a product or device will pass full-compliance testing at an accredited test facility, and without the need for additional problem solving which could translate into added expense. In this case, the closer the engineer’s pre-compliance measurements are to full-compliance measurements, the greater the confidence that the product in question will pass final evaluation. This is exactly where the modern spectrum analyzer comes in. Its performance and functionality make pre-compliance and full-compliance measurements easier, faster and as accurate for the novice as for the expert engineer. Of course, fully realizing these benefits, demands that the engineer first selects the right spectrum analyzer for his or her specific needs. Understanding EMI Measurements Before choosing a spectrum analyzer, it is helpful to first gain a clearer understanding of how the instrument will be utilized for EMI testing. First and foremost, achieving the goal of a close match between pre-compliance and full-compliance measurements requires a careful evaluation of both conducted and radiated emissions. Here, the spectrum analyzer serves as an excellent pre-compliance and diagnostic tool, helping the engineer to quickly and accurately determine the emissions profile of the device under test (DUT) and whether or not it will pass full compliance testing with a high level of confidence. With the proper capabilities, it can then also qualify as a fully compliant EMI measurement receiver. october 2007 conformity 43 http://www.ar-worldwide.com http://www.ar-worldwide.com

Table of Contents Feed for the Digital Edition of Conformity Magazine - October 2007

Contents Editor’s Note Commission Proposes Changes for 57-64 GHz Spectrum Rules FCC Continues Actions Against Jamming Device Distributors Radio Operator Fined for Failing to Make Equipment Available for Inspection Commission Fines Unsolicited Fax Advertisers Firm Offering Quality Standards Training Also Fined Breaking New Ground with Lithium-Battery Generic Requirements for Use in Telecommunications Facilities ESD Open Forum EMC UK 2007 Conference Set Staying Abreast of U.S. E-Waste Legislation EU Commission Establishes RFID Expert Group Update on China's CCC Compliance Program System Level ESD Testing: The Waveforms An Alternative Approach to Surge Suppression Testing Equipment Buyer's Guide EU Scientific Committee Releases Updated Data on EMF Risks Updated Standards List For The EU’s EMC Directive Updated Standards List For The EU’s Directives on Measuring Instruments Call for Presentations for 2008 International ESD Workshop Announced CPSC Actions In The News IEC Standards Update Product Reviews UL Standards Update New Products From Our “You Can’t Make This Stuff Up” Department Looking Back: Items from Past Issues of Conformity Upcoming Events Advertisers

Conformity Magazine - October 2007

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