Appendix D: Test Procedure For Radiated Emissions - AOpen CD-952E/AKH Manual

4.4 Appendix D: Test Procedure for Radiated Emissions

Preliminary Measurements in the Anechoic Chamber
The radiated emissions are initially measured in the anechoic chamber at a measurement
distance of 3 meters. Desktop EUTs are placed on a wooden stand 0.8 meter in height. The
measurement antenna is 3 meters from the EUT. The test setup in anechoic chamber is the same as
open site. The turntable rotated 360?C. The antenna height is varied from 1-2.5m. The primary
objective of the radiated measurements in the anechoic chamber is to identify the frequency spectrum
in the absence of the electromagnetic environment existing on the open test site. The frequencies can
then be preselected on the open test site to obtain the corresponding amplitude. The initial scan is
made with the spectrum analyzer in automatic sweep mode. The spectrum peaks are then measured
manually to determine the exact frequencies.
Measurements on the Open Site
The radiated emissions test will then be repeated on the open site to measure the amplitudes
accurately and without the multiple reflections existing in the shielded room. The EUT and support
equipment are set up on the turntable of one of the 3 or 10 meter open field sites. Desktop EUTs are
set up on a wooden stand 0.8 meter above the ground.
For the initial measurements, the receiving antenna is varied from 1-4 meter height and is
changed in the vertical plane from vertical to horizontal polarization at each frequency. Both reading are
recorded with the quasi-peak detector and with the 120 kHz bandwidth. For frequency between 30
MHz and 1000MHz, the reading are recorded with peak detector and with the 1 MHz bandwidth.
At the highest amplitudes observed, the EUT is rotated in the horizontal plane while changing
the antenna polarization in the vertical plane to maximize the reading. The interconnecting cables were
arranged and moved to get the maximum according to ANSI C63.4-1992, and/or
EN55022:1994/A1:1995/A2:1997 / CISPR 22:1993/A1:1995/A2:1996. Once the maximum
reading is obtained, the antenna elevation and polarization will be varied between specified limits to
maximize the readings.
During the open site measurements, the peaks are selected, the scan frequency span width is
reduced to 0--1MHz, the audible modulation is monitored with a loudspeaker and the quasi-peak
reading or peak is recorded at the indicated frequency and at the specified bandwidth.
International Standards Laboratory
NVLAP Lab. Code: 200234-0; VCCI: R-341, C-354; NEMKO Aut. No: ELA 113; BSMI Lab. Code: SL2-IN-E-0013
Declaration of Conformity
-12-
Report Number: ISL-00A105FB