1、f I , CEN PRENw2591 (PART*B13) 92 m 3404589 O026875 T = A.E.C,M.A. STANDARD NORME A.E.C.M.A. A.E.C.M.A. NORM prEN 2591 Patt EI 3 Issue P 1 June 1992 DITE PAR LASSOCIATION EUROPEENNE DES CONSTRUCTEURS DE MATRIEL AROSPATIAL Technopolis - 175, rue Jean-Jacques Rousseau - F-92138 Issy-les-Moulineaux Cde
2、x -Tl. (1 ) 47.36.98.76 UDC Key words : ENGLISH VERSION Aerospace series Elements of electrical and optical connection Test methods Part BI 3 - Shielding effectiveness from I O0 MHz to I GHz Srie arospatiale Luft- und Raumfahrt Mthodes dessais Prfwerfahren von 100 MHz bis 1 GHz Organes de connexion
3、lectrique et optique Elektrische und optische Verbindungselemente Teil BI 3 - Schirmwirkung . Partie BI 3 - fficacit du blindage de 100 MHz I GHz This .Aerospace Series) pre-standard has been drawn up under the responsibility of AECMA (Association Europenne des Constructeurs de Matriel Arospatial).
4、It is published on green paper for the needs ofAECMA-Members. It has been technically approvedby the experts of the concerned Commission following comment by the Member countries. Subseqzent to the publication of this pre-standard, the technical content shallnot be changed to an extent that intercha
5、ngeability is affected, physically or functionally, without re-identificaion of the standard. After examination and signature of the AECMA Standard Checking Centre (NPSJ and formal agreement of the Official Services of the Member countries it will be submitted as a draft European Standard to CEN (Eu
6、ropean Committee for Standardization) for final vote. Nota - Extra copies can lie supplied hy 6.N.A.E.- Technopolis 54 199, rue Jean-Jacques Rousseau - 92138 ISSY-LES-MOULINEAUX CEDEX Edition approved for publication Comments should be sent within six months C2 Chairman after the date of publication
7、 decision Technopolis - 175, rue Jean-Jacques Rousseau 921 38 Issy-les-Moulineaux Cdex - FRANCE 1992-06-05 A.E.C.M.A. M. J. LE CUNFF 0 aecma 1992 CEN PREN*K259L (PART*BL3) 92 m 3484589 002b8b L W prEN 2591-813 Page 3 1 Scope and field of application . This standard specifies a method of measuring th
8、e Shieiding effectiveness of an element of connection fitted with highfrequency screen clamping backshells. It shall be used together with EN 2591. 2 References EN 2591 Aerospace series - Elements of electrical and optical connection methods - General Test 3 Preparation of specimens 3.1 Two alternat
9、ives : - the insert shall be removed, or, - the insert shall be installed without contacts and a hole shall be drilled through its centre. Aconductor of suitable geometry to match with the inside diameter of the elements of connection and high frequency screen clamping backshells shall be installed
10、inside these elements to provide a 50Q impedance coaxial line. Taped accessories may be used to provide a means of changing diameters to centre the conductor inside the elements of connection provided it does not introduce any significant discontinuity in the coaxial line. The voltage standing wave
11、ratio (VSWR) shall not exceed 1,s. 3.2 Unless indicated in the technical specification the following details shall be specified : - test frequency, - number of specimens, - type of element of connection and electromagnetic interference backshells, - attenuation. 4 Apparatus The electromagnetic radia
12、tion detector (see figure 1) consists of an outer shell so constructed as to provide a good 500 impedance match with the outside part of the mated shells of the element of connection, the coupling ring and screen clamping backshells. The voltage standing wave ratio shall not exceed 1,5. Previous pag
13、e f&. is blank CEN PREN*259L (PART*BL3) 92 I 3404589 O026877 3 E prEN 2591-i313 Page 4 A sliding circumferential short shall be positioned between the element of connection and the signal input end of the fixture for tuning the outer coaxial line for maximum output at each test frequency. The allowa
14、ble travel of this short shall be greater than a half wave length at the lowest test frequency, ie approximately 1,6 m for a 100 MHz frequency. The inner coaxial line shall be terminated in a high frequency fixed 500 load impedance behind the connector at the output end of the fixture. connector fro
15、in Radio frequency connector to detector 50 R load termination for inner coaxial line under test Travel of shori A must exceed 2 Figure 1 - Radiation detecting equipment 5 Method 5.1 Test fixture The test fixture shall comply with figure 2. The signal input shall be fed through a 10 dB isolation pad
16、 to a parallel circuit consisting of a coaxial switch so connect.ed that the signal can be fed alternatively to the radiation detecting equipment and to a variable 1 O0 dB reference attenuator. The attenuator shall be adjustable in 1 dB steps and calibrated to & 3 dB. The level of detected signal po
17、wer shall be indicated by a tunable high frequency field intensity meter isolated from the test circuit by a 3 dB to 10 dB filter. Care shall be taken to ensure that the signal is a result of high frequency leakage from within the element of connection and not due to a faulty termination inside the
18、fixture. CEN PREN*257L (PART*B13) 72 m 3404587 002b878 5 m prEN 2591 -BI 3 Page 5 (- The connectors used to couple together the various elements of the test circuit shall be of a low-leakage type which have a nominal impedance of 509, a voltage standing wave ratio of less than 1,5 and a minimum leak
19、age attenuation of 1 O0 dB. The output impedance of the signal source and the input impedance of the detector shall be nominally 509 with voltage standing wave ratio of I ,5. The input and output voltage standing wave ratio of the standard attenuator shall be less than 1,5 in the 20 dB to 100 dB ran
20、ge. All terminations inside the fixture, whether to the high frequency backshells of the test element of connection or t the backshells of the connectors used to couple the measuring instruments or between internal conductors shall have a leakage at least 1 O dB less than the test requirements. c Ra
21、dio frequency -.- Coaxialswitches Standard at tenua tor Figure 2 - Test assembly 5.2 Procedure The shielding effectiveness of an element of connection with high frequency backshells is measured in an electromagnetic interference detector. The electromagnetic interference leakage from the conductor i
22、nside the test element of connection into the outer coaxial line shall be measured at the frequencies specified by the technical specification within an accuracy of 2 5 %. Tune the outer coaxial line to obtain the maximum signal output by sliding the short. The level of detected signal power shall b
23、e read on a tunable radio frequency field intensity meter. The standard attenuator is switched to the power output and then to the field intensity meter input. The standard attenuator output signal level shall be adjusted to equal the signal level read before. The signal loss in the leakage detector
24、 can then be read directly from the setting on the variable attenuator. Check that the signal is really the result of electromagnetic interference leakage from within the mated element of connection and not of faulty terminations inside the fixture. CEN PREN*259L (PART*BL3) 92 I 3Li04587 002b879 7 I prEN 2591-BI3 Page 6 5.3 Requirement The attenuation shall not be less than that specified by the technical specification.
