1、20 August 1971 s # I a z. . MILITARY STANDARD EFFECTIVENESS OF CABLE, CONNECTOR, AND WEAPON ENCLOSURE SHIELDING AND FILTERS IN PRECLUDING HAZARDS OF ELECTOMAGNETIC RADIATION TO ORDNANCE; MEASUREMENT OF Obtained From GLOBAL ENGINEERING DOCUMENTS 2625 %.Hickory St. Santa Ana, CA 92707 # (714)540-9870:
2、 (800)854-7179 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-, I- -._.- - MIL-STD-1377 MI m 7777731 008384i.1 O m ri , I ,_ MIL-STD-1377 (Navy) DEPARTMENT OF THE NAVY NAVAL ORDNANCE SYSTEMS COMMAND WASHINGTON, D. C, 20360 Effectiveness of Cable, Co
3、nnector, and Weapon Enclosure Shielding and Filters in Precluding Hazards of Electromagnetic Radiation to Ordnance; Meas urement of 1 MIL-STD-1377 (NAVY) 1, Navy. 2. to the Commanding Officer, Naval Ordnance Station, Indian Head, Md. Attn: Standardization Division, FS6. This Military Standard is man
4、datory for use by the Department of the Recommended coSrections, additions, or deletions should be addressed 20640, . ii I I i .- :. i, . . $ I i, . . - Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-. ,- : .- . . - :a . - s .- - t - MIL-STD-1377 (N
5、avy) CONTENTS Paragraph . Page 1. 2. 3. 4, 4.1 4.1.1 4. 1.1 e 1 4.1.1.2 4,1.1.3 4.1.1.4 4.1.1.5 4.1.1.6 4.1.2 4.1.2.1 4.1.2.2 4.1.2.3 4.1.2,4 4.1.3 4.1.4 4.2 4.3.1 4.3.2 4,. 3.3 403.4 4.4 4.2.1 4.2.2 4.2.2.1 4.2.2.2 4.2.3 4.2.4 40 3 4.4.1 4,4.1.1 4.4.1.2 4.4.1.3 4.4.1.4 4.4.1.5 4.4.1.6 4.4.1.6.1 SCO
6、PE., o o . 0 o o.* 1 REFERENCED DOCUMENTS . 2 DEFINITIONS 2 REQUIREMENTS a . . e o e 3. Shielding effectiveness measurements on cables (100 kHz to 30 MHz) . 3 Test apparatus 3 Signal generator . 3 eter 3 Cable adapter, 3 ShieXded short 3 RFvoltmeter . 3 Shielding . 3 Preparation for test . 4 Cable c
7、onnectors . 4 Longcables,. 4 Branch cables -. 4 RF environment . 4 Measurement technique . 4 Calculating the STI 5 (100 kHz to 30 MHz) . 5 Test apparatus . 5 Preparation of test connector . i Adaptercables 5 Pin extension insert . 5 Measurement technique . 5 Calculation of the STI 6 Shielding effect
8、iveness measurements on weapon enclosures (100 kHz to 30 MHz) . 6 Test apparatus 6 Preparation of test enclosure . 6 Measurement technique . 6 Calculation of STI 7 Shielding effectiveness measurements on cables (1000 MHz to 10 GHz) 7 Test apparatus 7 Signal generator . 7 Double stub tuners 7 Directi
9、onal coupler 7 Isolator . 7 Power meters . 7 Test cabinet . Cabinet enclosure . Shielding effectiveness measurements on connectors ii i Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1377 (Navy) 4.4.1.6,2 4,4,1.6.3 4.4.1.6.4 4.4.1.6.5 48482
10、4.482.1 4,4.2.2 4.4.3 484.381 4.4.3.2 4.484 485 4.581 4.5.1.1 4.5.1.2 4,5,1.3 4.5.1.4 4.5,l.S 4,5,1.6 4.5.2 4.5.2.1 485.2.2 485.2.3 4.5.284 485.3 4.583.1 4.5i3.2 48584 4.6 4.681 4.6.1.1 4.6,l.Z 4.6.1.3 4.6.2 4.6 3 4,6,3.1 4,6.3,2 4,6.3,2.1 4,6 3.2,2 4,6,4 487 4878 1 = 4,781.1 Page 8 8 8 8 9 9 9 9 9
11、10 10 Input antenna. Output antenna Access door . Paddle wheel tuner Preparation of test cable . Short termination . Connector adapter . Measurement technique . Shield loss measurement Calibration measurement Calculating shielding effectiveness Shielding effectiveness measurements on weapon enclosur
12、es (1000 MHz to 10 GHz) . 10 Test apparatus Signal generator 10 Double stub tuners 10 Directional coupler . 10 Isolator . 10 Powermeters . 10 Test cabinet 11 Preparation of the weapon enclosure 11 Reference discontinuity 11 Output antenna Paddle wheel tuner 11 Accesspanel . 11 Measurement technique
13、. . , , . , , , , . . . $ 11 12 Shield loss measurement 12 Calibration measurement 12 Calculating shielding effectiveness Effectiveness measurements below 30 MHz on filters for 12 loadknown . 12 Test apparatus . 12 RFvoltmeter Signal generator 12 Impedance measuring device Preparation of test filter
14、 Impedance measurements . , , , , . , , . , . . , . , 13 10 10 12 13 Measurement technique . . , , . , , , . . . . 13 Determination of filter loss , , , , . , , , , . , , , 13 Filter effectiveness measurement technique , . . . 13 Voltage measurements . 13 Calculating filter effectiveness , , , , . ,
15、 . . , . 14 Effectiveness measurements below 300 MHz on filters for load not known . , , , , , , . , , 14 14 Test apparatus Measuring instruments . 14 . iv _I_c , .T- r/-.-I.- . .- . . , _. . . . . MIL-STD-1377 (Navy) 4.4.3.2 Calibration measurement. The test cable shall be disconnected . from the b
16、ulkhead connector in the cabinet wall and the output antenna in the cabinet shall be connected to the bulkhead connectors center conductor. applied to the input of the cabinet. adjusted for a maximum power in the load as measured by the output power meter, matching devices tuned, the maximum output
17、power (Poc) and forward input power (Pic) to the cabinet are measured. With this configuration, the signal source power shall be The matching devices shall be This tuning is accomplished as described in 4.4.3.1. With the 4,4,4 Calculating shielding effectiveness. At each test frequency, shielding ef
18、fectiveness may be computed from the measured values of forward input power (Pis) and maximum output power (POS) for the shield loss measurement, and forward input power (Pic) and maximum output power (Poc) for the calibration measurement by using the following formula: Shielding effectiveness = 10
19、log (Pis Poc)/(PoS Pic). 4.5 Shielding effectiveness measurements on weapon enclosures (1000 MHz to 10 GHz). 4.51 Test apparatus. The test apparatus shall be arranged as shown in figure 6, 4.5,l.l Signal generator, The signal generator shall be in accordance with 4.4.1.1. 4.5,1.2 Double stub tuners,
20、 These shall be in accordance with 4.4.1.2. 4.5 , 1 , 3 Directional coupler , This shall be in accordance with 4 .4,1,3, 4,5,1,4 Isolator. This shall be in accordance with 4.4.1.4. 4,5,1.5 Power meters. These shall be in accordance with 4.4.1.5. 4.5.1.6 Test cabinet. This shall be in accordance with
21、 figure 9 and 4.4.1.6.1, 4.4,1,6,2, 4*4,1.6,4, and 4.4.1.6.5. the term “weapon cable“ shall be replaced by “weapon enclosure.tf) (In these paragraphs, . 10 I # I I .- . , . I Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1377 (Navy) * 4:5.2
22、 Preparation of the weapon enclosure. The internal components of the weanon shall be removed so that only the weapons shell or exte- rior skin Iremains. cabinet by low loss insulating material. The weapon enciosure shall be supported inside the 4.5.2.1 Reference discontinuity. A type N feed-through
23、bulkhead con- nector shall be installed in one wall of the weapon enclosure. chosen for this installation should be centrally located or near a suspected discontinuity, the bulkhead connector, These antennas shall consist of a 1-foot length of wire connected to the connectors center conductor. Provi
24、sion shall be made to remove the antenna outside the weapon enclosure and replace .- it with a standard type N short termination, The point An antenna shall be fitted to each side of 4.5.2.2 Output antenna, A type N feed-through bulkhead connector shall be installed in the weapon enclosure. installa
25、tion should be centrally located. the weapon enclosure on the inside shall be connected to the connectors center conductor, connected to the inside of the weapon enclosure, coaxial cable shall connect the other side of this connector to another feed-through connector located in the cabinet wall. The
26、 point chosen for this A wire running the length of The other ends of this wire shall be electrically A double shielded -_ r. I 4.5.2.3 Paddle wheel tuner. A paddle wheel tuner shall be installed inside the weapon enclosure. 4.4.1.6.5. However, if the dimensions of the paddle wheel tuner are too lar
27、ge for the enclosure, it shall be scaled down proportionally, Provisions for tuning from a position external to the cabinet shall be made by passing the rod through the weapon enclosure and cabinet walls. At the exit points, the rod shall pass through a tube which is less than 0.5 inch in diameter a
28、nd greater than 3 inches in length, shall be electrically bonded to their respective surfaces at the exit points in such a manner as to maintain the shield integrity of each enclosure, The tuner shall be in accordance with The tubes 4.5.2.4 Access panel. An access panel can be placed in the weapon T
29、he panel shall be as enclosure if necessary to facilitate the test, small as practical, The panel shall be bonded to the weapon enclosure by fasteners not more than 2 centimeters apart around the periphery of the panel. Standard RF gasket material shall be used to seal the panel. 4.5.3 Measurement t
30、echnique. The following measurements shall be conducted at 500-MHz intervals from 1000 MHz through .10 GHz. 11 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1377 (Navy) 4.5.3.1 Shield loss measurement. The reference discontinuity shall With
31、 the signal source power applied to the input be short circuited, - of the pow er. mecifi cabinet, the matching devices shall be tuned for maximum ouput The tuning procedure for each paddle wheel tuner shall be as ed in 4.4.3.1. The paddle wheel tuners should be tuned before With the matching device
32、s tuned, the maximum ouput tie stub tuners, power and forward input power to the cabinet are measured. 4,5.3,2 Calibration measurement, The short termination shall be removed from the reference discontinuity and replaced by the reference discontinuity antenna, shall be applied to the input of the ca
33、binet and the matching devices adjusted for maximum output power, specified in 4.5.3.1. power and forward input power to the cabinet are measured. With this configuration, the signal source power This tuning is accomplished as With the tuning devices tuned, the maximum output 4.5.4 Calculating shiel
34、ding effectiveness. Shielding effectiveness is computed from the measured values by using the equation specified in 4.4.4. 4,6 Effectiveness measurements below 30 MHz on filters for load known. Filter efectiveness can be determined as specified in 4.7 rather than 4,6, if desired, 4.6.1 Test apparatu
35、s, The test apparatus.shal1 be in accordance with figure 10. $ 4.6.1.1 RF voltmeter. Any RP voltage measuring device(s) which has the desired frequency range and sensitivity shall be used. impedance of the voltmeter shall be high enough such that the impedances in the transmission lines being monito
36、red are not significantly changed, The input 4.6.1.2 Signal generator. The signal source shall be any signal generator or pver oscillator capable of providing sufficient power output to permit a filter effectiveness of 60 db to be measured with the voltage measuring device described in 4.6.1.1. 4.6.
37、1.3 Impedance meksuring device. Any RF bridge or other device or arrangement capable of measuring impedances in the range encountered shall be used. 12 . . . . . . . . . - .,. . . ,.-.- . . ._.- .-. - -. ._Ci- - -:. ,- -. .I : . . . Provided by IHSNot for ResaleNo reproduction or networking permitte
38、d without license from IHS-,-,-t MIL- STD - 1377 (Navy) 4.6.2 Preparation of test filter. The filter shall be mounted in its . final production configuration with the load (circuit to be protected) unattached. 4.6.3 Measurement technique. A low loss filter generally is not suitable for protection of
39、 a load when not all the circuit impedances are known and a meaningful filter effectiveness cannot be measured, Therefore, a preliminary test shall be required to determine whether the filter under test is a high or low loss device. 4.6.3.1 Determination of filter loss. The input impedance of the fi
40、lter shall be measured with the ouput of the filter terminated in a short circuit and again with it terminated in an open circuit. terminations shall be placed at the same point in the output circuit, These measurements shall be made at frequencies not more than 1 octave apart over the specified fre
41、quency range. The following formula shall be used to determine filter loss: The Filter loss = p+w%l where ZSC is the filter input impedance with the output shorted and ZOC is the filter input impedance with the output open. If the filter loss is less than 10, filter effectiveness measurements are no
42、t meaningful. If the filter loss is greater than 10, filter effectiveness can be determined using the method in 4.6.3.2. 4,6.3.2 Filter effectiveness measurement technique, The arrangement of the measuring equipment and test apparatus shall be in accordance with figure 10. 4.6.3.2.1 Impedance measur
43、ements. The input impedance shall be measured at the input terminals of the filter with the load attached, The load impedance shall be measured by removing the filter from the circuit and measuring the impedance between the load terminals. The values of the input and load impedances shall be measure
44、d at frequencies not more than 1 octave apart from 100 kHz to 30 MHz. 4.6.3.2.2 Voltage measurements, The input voltage and the output voltage of the filter under loaded conditions shall be measured, the filter properly installed in the circuit, the signal source voltage With 13 . . . . . - - - . .
45、._ . Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-STD-1377 (Navy) shall be applied to the input terminals of the filter and shall be mea- sured with the RF voltage measuring device. shall be made at the point in the input circuit where the imp
46、edance was measured, a similar manner. for the filters output circuit, the voltage measuring device should be placed outside the weapon with the probe and probe cable penetrating the weapon enclosure, The probe cable shield should be bonded to the weapon enclosure at the entry point to maintain the
47、integrity of the enclosure shield, the impedances in, 4.6.3.2.1 were measured, The voltage measurement The output load voltage shall be measured simultaneously in If the weapon enclosure provides the circuit shield Voltage measurements shall be made at those frequencies at which 4.6.4 Calculating fi
48、lter effectiveness; From the measured values of filter input voltage (Vin), load voltage (VL), filter input impedance (Zin), and load impedance (ZL), the filter effectiveness at each frequency can be calculated using the following formula: where Rin and RL are the real parts of Zin and ZL, respectiv
49、ely, and the brackets, I I, designate the magnitude of the impedances. 4.7 Effectiveness measurements below 300 MHz on filters for load not known, - 4,7.1 Test apparatus. The test apparatus shall be arranged as shown in figure 11, 4,7.1,1 Measuring instruments. The voltmeter, signal generator, and impedance measuring device shall be as specified in 4.6.1.1 through 4.6,1.3. 4.7.1.2 Filter load. T
