Conformity Magazine - February 2009 - (Page 38)

Figure 12b depicts the SI analysis of two nets (RX/RX) when a PRBS (rising time TR=0.001ns) is used to excite one of them. A rising/falling time of 0.001ns is used. On the left side, input/output are represented and only a small attenuation is observed, with almost no ringing on the output waveform. However, some noise and coupling can be spotted (see Figure 12c) in both the near-end (NE) and far-end (FE) crosstalk results. Figure 13 illustrates the field source corresponding to the analyzed PCB used to excite the optical transceiver within the frequency range 0-40GHz. It also illustrates the high complexity of the device, which includes many details with extremely small dimensions. Even thought the frequency range is broadband in this case, the first software application is used in this simulation for two reasons. First, calculation of punctual values of the E/H field plot generated by the simulation without any form of interpolation ensures accurate results for specific frequency values. Second, using specific meshing techniques allows us to directly simulate the model as a mechanical CAD file, without any form of pre-simplification and/or healing. It is this reason in particular that allows us to consistently reduce the time necessary to set up the model. Two different simulations are performed in order to analyze the radiated emission of the transceiver, with the first simulation in the frequency range 5-30GHz, and the second within the low frequency range 0-1GHz. Although the broadband range being test is 5-30GHz, the simulation is not computationally expensive, due to the relatively small calculation domain necessary to achieve accurate far field results. a a b c Figures 11a and 11b: a) Top view of the PCB inside the optical module; b) PEEC mesh view and equivalent SPICE model 38 Conformity february 2009 b Figures 12a 12b and 12c: a) S-parameters results for the nets of interest in the PCB; b)-c) SI analysis on TX and TX nets (input/output and NEXT/FEXT)

Table of Contents Feed for the Digital Edition of Conformity Magazine - February 2009

Conformity Magazine - February 2009 Contents Editor's Note FCC Clarifies Closed Captioning Requirements for DTV Receivers Commission Cracks Down (For the Fifth Time!) On Junk Fax Marketer FDA Requests Comments on Global Harmonization Documents Australia Now Requires Solar Panel Testing and Certification EU Drafting New Directive on Toy Safety EU Commission Revises Standards List for EMC, R&TTE Directives Additional Standards Published For the EU's Medical Devices Directive EU Commission Publishes Additional Standards for Directives on Active Implantable, In Vitro Medical Devices EMC For the Functional Safety of Automobiles ESD Open Forum The ILAC Arrangement: Facilitating Trade Efficient Methodology for the EMI Analysis of Optical Transceivers Including PCBs and/or Flex Circuits The EuP Directive - Implementation, Design Requirements and Issues Chambers, Shielding, and Accessories Buyer's Guide CPSIA Lead Requirements Apply to Existing Inventory, Says CPSC CPSC Clarifies Certifcation Requirements Other CPSC Actions in the News IEC Standards Update Product Reviews UL standards Update Telcordia Standards Update From Our "You Can't Make This Stuff Up" Department Looking Back: Items from Past Issues of Conformity Advertisers

Conformity Magazine - February 2009

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