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Program for RFI Spectrum Analysis

IP.com Disclosure Number: IPCOM000062700D
Original Publication Date: 1986-Dec-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 2 page(s) / 44K

Publishing Venue

IBM

Related People

Lanham, TE: AUTHOR

Abstract

In radio frequency interference (RFI) testing a spectrum analyzer provides data giving radiation levels over a frequency range divided into 1001 lines or bands. The program level searches for the largest peaks in the spectrum within a given margin of a specific level. When the largest peak is found, it and close lines on either side are deleted; the program then looks for the next largest peak. An item under test is placed on a turntable. An antenna at variable/distance height detects electromagnetic interference using a spectrum analyser as the item is rotated. At each selected antenna position the spectrum analyzer records radiation levels for 1001 lines as required in international specifications.

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Program for RFI Spectrum Analysis

In radio frequency interference (RFI) testing a spectrum analyzer provides data giving radiation levels over a frequency range divided into 1001 lines or bands. The program level searches for the largest peaks in the spectrum within a given margin of a specific level. When the largest peak is found, it and close lines on either side are deleted; the program then looks for the next largest peak. An item under test is placed on a turntable. An antenna at variable/distance height detects electromagnetic interference using a spectrum analyser as the item is rotated. At each selected antenna position the spectrum analyzer records radiation levels for 1001 lines as required in international specifications. The requirement is to determine which frequency lines peak above varying level frequency lines specific by international standards. The flow chart shows the peak search program. The program input is a measured 1001 spectrum with the required international limits subtracted (which may vary in shape and number of steps) and 20 dB added. This eliminates low level frequency lines which are of no interest. The program finds the line with the maximum level and proceeds if the level exceeds (20-L)dB, i.e., within or lower by LdB of international standard. L has a nominal value of 6dB and can be changed by the operator. The next steps set the maximum line to zero and adjacent M lines to zero to allow for analyzer filter shape. M has a nomina...