User`s guide

A-6 Appendix A
5MHz and 10MHz have been demonstrated to comply with both FCC-B and EN
55022-B limits with margin.
Comparison of FTT-10 and FTT-10A Radiated EMI
A typical test setup was scanned at an outdoor EMI test facility in order to compare
radiated emissions from the FTT-10 and FTT-10A transceivers. The test setup is
shown in figure A.3 .
Floor-Mounted Power Strip
Wooden Test Table
FTT
EMI
Echo
Unit
FTT
Device
Under
Test
1 Meter Network Cable
Figure A.3 Test Setup for EMI Comparison of FTT-10 and FTT-10A
Transceivers (Top View)
The “FTT EMI Echo Unit” contains a 5MHz Neuron 3120 Chip and an FTT-10
transceiver on a 2-layer PCB. The layout of this PCB is identical to that shown in
chapter 2 of the FTT-10 Free Topology Transceiver User’s Guide. The Echo Unit
contains no ferrites or other EMI suppression devices in the network connection. The
Neuron Chip in the Echo Unit runs a Neuron C program which continuously queries
the status of the Device Under Test.
The “FTT Device Under Test” (DUT) is based on the Echelon’s LONWORKS Router. A
single control module is placed into the router to serve as the test unit: a production
TP/FT-10 control module was used for the 5MHz FTT-10 baseline scans; an FTT-10A
transceiver in a production TP/FT-10 control module was used for the 5MHz scans;
and an FTT-10A control module (not a production product) was used for the 10MHz