Applicability of ISO standards & noise estimation tool

Sammanfattning: This study has two major purposes: (1) To determine the applicability of ISO standards for calculating sound power levels emitted by acoustic noise sources in-house at Ericsson, Kista. (2) To design a software tool for estimation of emitted sound power levels from a radio installation. To determine the applicability of different ISO standards during the design phase at Ericsson, viable standards were chosen and measurements were taken on the exact same noise source following each chosen standard. The evaluation of these measurements was made with different points in focus.  Accuracy  Availability of instrumentation and measurement environments  Time consumption  Complexity of measurement conduction. The ISO standard that showed most promise was the ISO 3744. This standard uses a method with fairly high accuracy and is quite easy to implement compared to other standards tested. All instrumentation required to follow this standard, except for a calibrated microphone calibrator, is available at Ericsson, Kista. The standards ISO 3747 and ISO 9614-2 might also be of interest, during the design phase, if the equipment necessary is acquired. The acoustic noise estimation tool was written in the Microsoft Excel embedded programming language, Visual Basic for Application version 7.1. With the tool it is possible to specify the layout of a radio installation for mobile traffic with different mounted radios and estimate both the sound power level emitted from all these radio units and the sound pressure level at a distance from the radio installation. It is also possible to define new radio units in the tool and save them for later use. The tool was verified by acoustic measurements taken on a test setup at MWL, KTH.