Click on the following bookmarks for further details of an Audit Stage:
The Audit Process
Stage 1: Summarises the project name, the emissions specification levels, any identified noise signals. Compares the noise levels with the emissions specification, and states whether these exceed the specification before the shielding is taken into account.
Stage 2: Summarises the enclosure size, material and finish.
Stage 3: Provides the basic shielding level of the enclosure walls, at a range of frequencies, and calculates the first sixteen resonant frequencies.
Stage 4: Calculates the external field levels caused by leakage through the enclosure walls of identified sources. The external field produced in this manner will normally be very low, unless the enclosure walls are thin. This could be the case in a vacuum deposited coating on plastic for example.
Stage 5: Examines the leakage due to the enclosure seams, and calculates the frequencies where the attenuation is expected to be 40dB, and 0dB. No leakage is reported if the seam is solid or gasketed.
Stage 6: Examines the enclosure seams again, and compares the actual external field level with the emissions specification.
Stage 7: Summarises the apertures, and calculates the 40dB and 0dB attenuation frequencies. Additional shielding components are not taken into account at this stage.
Stage 8: Examines the apertures again, and compares the external field with the emissions specification, and states the margin. Additional shielding components are not taken into account at this stage.
Stage 9: Examines the apertures again, and takes into account any additional shielding components such as shielded windows. External field levels are again compared with the specification.
Stage 10: Summarises the access panels, their properties, description, and fixing means. If the panel is fixed by fasteners, without a gasket, a narrow aperture is assumed to exist between each fastener. In this case the frequencies for 40dB and 0dB attenuation are calculated.
Stage 11: Compares the panel edge leakage fields with the emissions specification, and states the margin.
Stage 12: Summarises the panel mounting components. Where these produce an aperture, the 40dB and 0dB frequencies are stated.
Stage 13: Compares the panel mounting component leakage fields with the emissions specification, and states the margin.
Stage14: Summarises the conductor interface properties.
Westbay Technology Ltd, Main Street, Baycliff, Ulverston, Cumbria LA12 9RN, England
Tel: 01229 869 798 (from the United Kingdom) Tel: +44 1229 869 798 (International) Contact by e-mail