Conformity Magazine - September 2007 - (Page 15)

data were transformed to the time domain, where gating was applied and the data transformed back to the frequency domain. Finally, the two antenna method [7] and the Friis equation [8] were applied to the time-gated insertion loss data to obtain the free space antenna factors. For this evaluation, the antennas were placed on towers constructed from PVC pipe at a height of 5 meters. To study the effects of antenna coupling and site reflections, separation distances of 3, 5, 10 and 20 m were used. The antennas were measured only in the vertical polarization. CW transmission data (magnitude and phase), S21, were obtained over the antenna pair’s frequency range. Measurements were repeated to check the positioning sensitivity of the antenna. Cable and equipment effects were removed with a response calibration prior to measurements and checked after measurements were completed for system thermal stability and connector repeatability. The frequency step size was set to remove data aliasing in the time domain. This resulted in small step sizes ( 45000 frequency points). RF cable lengths were minimized with the use of RF/fiber optic links. These Antenna Biconical dipole large DRG DRG Time (ns) 15-22 10-20 6-8 Table 1: Useable antenna ring-down times Antenna Setup Geometry D = 3 m, h=5 m D = 5 m, h=5 m D = 10 m, h=5 m D = 20 m, h=5 m Direct Path (ns) 9.8 16.4 32.8 65.6 Ground Reflected Path (ns) 34.2 36.7 46.4 73.3 Figure 3: Signal processing sequence to obtain free-space insertion loss data Table 2: Useful direct and ground reflected path times EMC Excellence. If you strive for EMC compliance, reliability and safety, Schaffner has the right solution readily available. If you need something special, we are pleased to design it for you. Benefit now from more than 40 years of experience! EMC filters RFI suppression chokes Power Quality Feedthrough components Power transformers Engineering & testing services Schaffner EMC Inc. 52 Mayfield Avenue Edison, New Jersey 08837 T +1 732 225 9533 Toll free 1 800 367 5566 F +1 732 225 4789 www.schaffnerusa.com Components_6_875x4_875inch.indd 1 September 2007 Conformity 15 31.07.2007 10:41:16 http://www.schaffnerusa.com http://www.schaffnerusa.com

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

Contents Editor’s Note FCC Extends Disability Access Requirements to VOIP Commission Fines Importer $3 Million Over Non-Compliant TVs FCC Gets Tough on Retailers Over Analog TV Tuner Labeling Analog Cellular Service Sunset Date Reaffirmed Commission Adopts Recommendations of Katrina Panel Free-Space Antenna Factors Through the Use of Time-Domain Signal Processing Editorial Correction ESD Open Forum An Update on Revisions to IEC 61000-4-2, the Basic Standard on ESD Practical Advice for Meeting the DFS Testing Requirements of the FCC The EMC Impact of Embedded Software ESD Design Buyer's Guide Tate Renominated to the FCC EPA Releases Report on U.S. Electronic Waste Additional Standards For The EU’s Toy Directive Medical Device Manufacturer Enters Consent Order Updated Guidance Document on Laser Products Issued FDA Offers Advice on Defective Heating Pads CPSC Issues China Product Safety Program Report Other CPSC Actions In The News IEC Standards Update Product Reviews Product News UL Standards Update From Our “You Can’t Make This Stuff Up” Department Looking Back: Items from Past Issues of Conformity Advertisers

Conformity Magazine - September 2007

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