Kagakora This process uses a direct drive method up to the first airframe electrical resonance, and a radiated field test methods above the first airframe resonance. Therefore, the need for EMI testing has never been more important for all commercial and military aircraft in use today. This approach is preferred over high level testing for its reduced RF exposure levels and RF hazard considerations. Already Subscribed to this document. Local Stock Images—Downtown Greenville — Amy Randall You can download and open this file to your own computer but DRM prevents opening this file on another computer, including a networked server. If the document is revised or amended, you will be notified by email.
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The top level document — and the only document that defines a legal requirement for manufacturers — is FAA CFR parts This document defines one acceptable path to demonstrate compliance with the CFR.
However, it is not a regulation and does not constitute a legal requirement for manufacturers. This document deals only with testing at the box level and does not have any information on aircraft level testing. It is, however, referenced by ARP In summary, there is no regulation that specifically states exactly how to perform tests for HIRF certification.
A manufacturer is free to define its own test procedures as long as they are accepted by the FAA. The values in these tables are root mean square RMS values not amplitudes, and any calculated data should be reported as RMS values.
Each section also provides 3 test levels for systems of different criticality. There are no requirements for aircraft level tests. On page 1 in section 1. It describes an acceptable means, but not the only means, for you to show compliance with the requirements for protection of the operation of electrical and electronic systems when the aircraft is exposed to an external HIRF environment. Flow charts for each system classification show how to achieve HIRF compliance.
Figure 1 on page 17 is for category A systems, Figure 2 on page 18 is for category B systems, and Figure 3 on page 19 is for category C systems. In these flow charts and the text to explain them is the first mention of specific aircraft level test procedures: Aircraft high level tests and Aircraft low level coupling tests.
There are some specifics for the tests given on pages , but there is not enough detail to actually perform a test. AC also provides some general transfer functions for conducted susceptibility derived from measurements of multiple aircraft. The aircraft level tests fall into two categories: high level tests and low level tests. There are two types of tests: direct drive and radiated. The relationship of the direct drive test to actual irradiation is unclear. The field values and modulation schemes are given in Table 9 on page 57 of the ARP.
The radiated tests are performed using antennae or microwave horns from the first aircraft resonance to 18 GHz with the possibility of testing up to 40 GHz. The radiated tests are intended to measure two quantities: conducted susceptibility on cables and field values interior to the aircraft.
Conducted susceptibility is measured over the range of 10 kHz to MHz, and field values are measure from kHz to 18 GHz with an option to go to 40 GHz if necessary. Testing above 18 GHz is only necessary if there are systems that operate a frequencies above 18 GHz, or if susceptibilities are found in the GHz range.
Alternately, the tests can be conducted with a continuously swept frequency source. Section 6. The low level tests are similar to the high level tests with the exception that lower field values are used. Unlike the high level test, the low level tests do not have any information on the number of measurement frequencies or the modulation schemes.
However, later sections of the ARP that deal with system and subsystem testing have the same modulations schemes as for the high level testing. We could conclude from this that the modulations schemes for high level testing apply across the board and include the low level testing.
Pages 70 and 71 in section 6. As with the high level tests, the direct injection stops at the first aircraft resonance. The LLSC test requires measuring the incident field in the absence of the aircraft to find the field value for normalizing the measured currents.
The ARP also suggests using a mechanical mode stirrer or broad band illumination p. It is however referenced by ARP It also has categories for the maximum conducted susceptibility for different types of systems. These levels appear to be loosely based on the generic transfer functions in AC Appendix 1, p. If comparisons are desired between predictions and measurements, it is necessary to obtain detailed information concerning the measurement instrumentation, including antennas and the way in which the measurements were made e.
For general HIRF computations, it is important to include in the model enough complexity, lossy material and structural accuracy to ensure adequate model fidelity. Get notified about new content and demos Related.
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