1、MIL-G-28744A( EC) -. 22 March 1978 SUPERSEDING MIL-G-28744 (ECI 14 April 1970 MI L ITARY SPEC IF I CATION GENERATOR, AIMS PRETRIGGER SG-841( ) /UPX This specification is approved for use by the Naval Electronic Systems Cornnand, Department of the Navy, and is available for use by all Departments and
2、 Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. 1.2 Operating modes. This specification covers a pretrigger generator which provides all necessary timing signalsfor shipboard AIMS system operation. either of the following two modes: The pretrigger generator covered. by this specification
3、 operates in Mode A: Mode B: Operation with radar sets utilizing a nonstaggered or nonjittered pulse repetition frequency (PRF). Operation with radars utilizing a jittered PRF. 2. APPLICABLE DOCUMENTS 2.1 Issues of documents. The following documents of the issue in effect on date of invi- tation for
4、 bids or request for proposal form a part of this specffication to the extent specified herein. SPECIFICATIONS MILITARY MIL-S-901 MIL-E-4158 MIL-E-164001 MIL-E-17555 MIL-C-39012/21 Shock Tests, H. i. (High-impact) , Shipboard Machinery, Equipment And Systems, Requirements For (Navy) Electronic Equip
5、ment , Ground, General Requirements For Electronic Equipment, Naval Ship And Shore: General Spec if icat i on Electronic And Electrical Equipment, Accessories, And Repair Parts, Packaging And Packing Of Connectors, Coaxial , Radio Frequency (Series BNC (Uncab led) -Receptacles , Female, Jam. Nut Mou
6、nted, Class II) Beneficial cornnents (recommendations , additions , deletions) and any perti nent data which may be of use in improving this document should be addressed to: Comnander, Naval Electronic Systems Command (ELEX-5043) , Washington, D.C. 20360, by using the self-addressed Standardization
7、Document Improvement ProDosal (DD Form 1426) amearinq at the end of this document. or bv letter. FSC 5840 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-G-287iiA 58 7777706 0354557 3 W MIL-G-28744A( EC) STANDARDS MILITARY MIL-STD-105 MIL-STD-108
8、 MIL-STD-109 MIL-STD-167-1 MIL-STD-275 MIL-STD-454 MIL-STD-461 MIL-STD-471 MIL-STD-781 Samolinq Procedures And Tables For Insoection BY Attri buies Definition Of And Basic Requirements For Enclosure For Electric And Electronic Eauioment, Quality Assurance Terms And Definitions Mechanical Vibrations
9、Of Shipboard Equipment (Type 1- Environmental And Type li - Internally Exited) Printed Wiring For Electronic Equipment Standard General Requirements For Electronic Equipment Electromagnetic Interference Characteristics Requirements For Equipment Maintainability Demonstration Reliability Design Quali
10、fication And Production Acceptance Tests : Exponent i al Distri bution 1Revision F applies. (Copies of specifications,. standards, drawings, and publications required by contractors in connection with specific procurement functions should be obtained from the procuring activity or as directed by the
11、 contracting officer.) 3. REQUIREMENTS 3.1 General. as herei namec if i ed . 3.1.1 Subassemblies and circuit-card assemblies. Subassemblies and circuit-card assembl ies which have been developed and tested under the requirements of MIL-E-4158 and which use materials and finishes in accordance with-M
12、IL-E-4158 will be acceptable for use in this equipment without need for redesign specifically to meet the requirements of MIL-E-16400. The equipment shall be in accordance with requirements of MIL-E-16400 except 3.1.2 First article. Prior to beginning production, a sample shall be tested as specifie
13、d in 4.3. 3.2 Design. - 3.2.1 Equipment composition. The equipment shall consist of solid state circuitry mounted on printed circuit cards, mounted in an enclosure which is dripproof in accordance with MIL-STD-108. 3.2.1.1 Printed circuit cards. All printed circuit cards used shall be designed and m
14、anufactured in accordance with MTL -STD-275. marked with an identifying number to distinguish it from any other type. shall be capable of operating in either mode A or mode B as described in 1.2. The equipment may convert from mode A operation to mode B operation by an interchange of modules within
15、the equip- ment. stored within the equipment during mode B operation, and modules which are used for mode B operation but are not used for mode A operation shall be stored within the equipment during mode A operation. Each type of card used in the equipment shall be 3.2.1.2 Operating configurations.
16、 The pretrigger generator covered by this specification Modules which are used for mode A operation but are not used for mode B operation shall be 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-.- MIL-G-287LtLIA 58 9979706 0154558 3 = MIL-G-28744A
17、( EC) 3.2.2 Electrical design. The equipment shall be capable of operating from a power source whose voltage and frequency characteristics are as follows: a. Voltage: 115 VAC 10 percent single phase b. Frequency: 50, 60 and 400 Hz +IO percent protection shall be provided by circuit breakers in lieu
18、of fuses. protection used, all equipment shall have an indicator on the front panel, near the primary power indicator, which shows when an overload has caused the protective device to function. control connectors shall be chosen from the AN or MS series. rear panel. proper system operation witti sig
19、nals which have a DC reference other than ground. ment shall not be waived unless the contractor demonstrates to the procuring activity and obtains approval of a design technique which is immune to such input signals. minus 0.1 volt plus 0.2 volt unless otherwise specified herein. 3.2.2.1 Overload p
20、rotection. Overload protection is required. Wherever possible overload Regardless of the type of 3.2.2.2 External connectors. All signal connectors shall be type Cy and all power and All connectors shall be on the 3.2.2.2.1 DC isolation. The video signal inputs shall be capacitively coupled to insur
21、e This require- 3.2.2.2.2 Output reference level. The video signal outputs shall be referenced to ground 3.2.2.3 Electromagnetic interference emission, susceptibility, and equipments and systems self-compatibi7ity. equipment except that CS03, CS04, CS05, (T) CS07 and CS08 are not required. The equip
22、ment shall meet the requirements of MIL-STD-461 f or Class IC 3.2.3 Mechanical design. 3.2.3.1 Size. The mechanical design of the equipment shall conform to the requirements of 3.2.3.1 through 3.2.3.6. shall be as foms: The maximum dimensions (including mounting provisions) of the equipment a. Heigh
23、t: 12.7 cm (5 inches) b. Width: 44.45 cm (17 1/2 inches) c. Depth: 30.48 cm (12 inches) 3.2.3.2 Weight. 3.2.3.3 Mounting. The weight of the equipment shall not exceed 9.07 kg (20 pounds). The equipment shall be designed for mounting to a flat surface without resilient mounts. to this flat surface. c
24、omponent chassis. withdrawn from the equipment case. releasing no more than six securing devices located on the front panel surface only. 3.2.3.5 Equipment case. rectangular box comprising the equipment enclosure. mounting to an equipment shelf by the bottom surface only. The rear panel of the equip
25、ment shall be a removable part of the enclosure and not a part of the equipment chassis. be installed on the removable rear panel except for test signal outputs (see 3.4.3.2) which shall be on the front panel. enclosure. replaceable moduies via the front of the equipment. Provisions shall be include
26、d for mounting the bottom surface of the equipment 3.2.3.4 Component chassis. The chassis assembly shall be composed of a front panel and a Access to the equipment interior shall be accomplished by All circuit boards and subassemblies shall be accessible when the chassis is The case shall form the t
27、op, bottom, and two lateral sides of a The case shall have provisions for direct 3.2.3.6 Rear panel. All signal input and. output connectors shall 3.2.3.7 Enclosure. The equipment shall be mounted by devices secured to the base of the The equipment shall be designed to permit ready access to interna
28、l test points and MIL-STD-454, Requirement 36 shall apply. 3 t Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-I_ MIL-G-28744A 58 7777706 0354557 5 MIL-G-28744A( EC) 3.2.4 Controls, indicators, and panel layout. 3.2.4.1 Tactile identification. Tactil
29、e identification of controls is not requir.ed. 3.2.4.2 Classification of controls. All controls shall be classified as continually required except those used primarily in initial installation and adjustment or for maintenance adjustment and alignment. shall not exceed ! mA to ground, whether or not
30、such equipment contains radio interference filters or capacitors. warning plate shall be attached to the front panel of each equipment reading: 3.2.5 Leaka e current (equipment). When practicable, the leakage current of the equipment Should the equipment have an unavoidable leakage current in excess
31、 of 5 mA, a DANGER - Do not energize this equipment unless frame and all exposed metal parts are grounded. 3.3 Reliability. 3.3.1 Quantitative reliability. The upper test mean-time-between-failure (MTBF) (e as defined in MT!XTD-/tll f or the pretrigger generator shall be 6000 hours. (0 ) shall be 20
32、00 hods. Failure is the inability to meet any of the performance control or moh itor i ng functions spec if i ed herein. The equipment shall be capable of passing a temperature equipment coKTitioning test, with the environment temperature equal to or greater than 50“C, with the equipment operating i
33、n the worst case mode for a continuous operating time of 72 hours of failure-free time. Failures occurring during this 72 hour period shall be repaired and the burn-in resumed until 72 hours of failure-free time is achieved. other than normal operating mode changes, shall be allowed during this test
34、. The lower testoMTBF 3.3.2 Equipment conditioning. No adjustments of the equipment, 3.4 Maintainabi 1 ity. 3.4.1 Quantitative maintainability requirements. The pretrigger generator shall have an equipment repair time (ERT) of 15 minutes when corrective maintenance by module or circuit card is perfo
35、rmed. ERT includes local izat i on, i sol at ion, disassembly, interchange, reassembly, alignment and checkout for all subassemblies and parts. 3.4.2 Maintainability demonstration. The maintainability requirements for the pretrigger generator shall be demonstrated in accordance with 4.6. 3.4.3 Servi
36、ce and access. The equipment design shall permit easy and ready access to internal parts, test points, and adjustments. Removal and replacement of subassemblies shall not require the removal or displacement of other subassemblies. under this specification shall be designed to permit ready access to
37、internal test points and replaceable modules via the front of the equipment in accordance with Requirement 36 of MIL-STD-454. 3.4.3.1.1 Captive fasteners. Loosening of captive fasteners on the front panel shall provide for withdrawal o? the equipment from the case, for maintenance. 3.4.3.1.2 Slides,
38、 guides, safety interlocks, and bypass switches. Slides or guides with safety stops to prevent accidental complete removal shall be employed Safety interlocks and bypass switches are required. of sufficient length to allow full extension of the unit from the case. Provisions shall be supplied to sup
39、port all cables coming from the rear panel to the removable component chassis, such that these cables sustain no damage. 3.4.3.1 Accessibility of internal test points and replaceable modules. Equipment procured - 3.4.3.1.3 Internal power and signal cables. The internal power and signal cables shall
40、be 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-OQ the equipment for measurement of these signals. 3.4.4 Reversibility. The equipment shall incorporate features such that it is mechanically or electrically impossible to install incorrectly its m
41、odules, circuit card assemblies, and sub- assemblies, except as required for compliance with the interchange of modules permitted (see 3.2.1.2). 3.5 Maintenance. 3.5.1 Test points and test features. Test points and test features are required and shall comply with 3.5.1.1 through 3.5.1.3. 3.5.1.1 Ext
42、ernal test,points. Test points shall be provided on the front panel to allow Mechanical design of the rapid, accurate isolation of malfunction to the defective equipment. front panel shall be as specified in 3.4.3.2. 3.5.1.2 Internal test points. Internal test points shall be provided on each circui
43、t board or module. immediately. The test points shall be of the probe type, suitable for insertion of a standard, flexible tip probe. Observation of these test points will identify a defective board or module Test points for printed circuit cards shall be brought to the top of the card. 3.5.1.3 Exte
44、nder board. A printed circuit extender board shall be provided. One extender shall accomnodate al I printed circuit boards of the equipment. It shall be stored in the card compartment when not in use. 3.6 Performance characteristics and detail requirements. 3,6.1 Performance characteristics. 3.6.1.1
45、 as described in 3.6;l.l.l and 3.6.1.1.2. Input signals. The equipment shall operate with input signals having characteristics 3.6.1.1.1 Radar trigger. a. Polarity: b. Amplitude: c. Duration: d. Rise Time: e. Fall Time: f. Source g. PRF: Impedance: Pos it ive 5 to 55 volts 0.30 to 25.0 microseconds
46、(psec) Up to 25 percent of pulse duration, or 0.04 psec per volt times pulse amplitude, whichever is smaller 1 to 5 times pulse rise time 75 ohms, resistive, 25 ohms 15 - 3000 pps mode A 15 - 2000 pps mode B 3.6.1.1.2 Input power. The equipment shallrequire no more than 25 volt-amperes primary power
47、. The equipments power factor shall be no less than 0.85. 3.6.1.2 Output signals. The equipment shall produce output signals with characteristics as specified in 3.6.1.2.1 through 3.6.1.2.3. 5 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-G-287
48、4YA 58 9999906 0354563 3 MIL-G-28744A( EC) 3.6.1.2.1 SIF pretrigger. The SIF pretrigger shall be as follows: a. Polarity: Posit ive b. Amplitude: 20 +5 volts c. Noise Level: O t0.5 volts d. Duration: 1.0 t0.2 usec e. Rise Time: 0.1 Iisec, maximum, 0.02 minimum f. Fall Time: 0.1 Ftsec, maximum, 0.02
49、minimum g. Termination Impedance: 75 15.0 ohms, resistive 3.6.1.2.2 Other trigger outputs. The following additional output triggers shall be pro- duced with characteristics identical to the SIF pretrigger as described in 3.6.1.2.1. a. Processor start trigger b. Mode 4 pretrig er c. Radar trigger !except for mode A, external triggering) output shall have two selectable amplitudes, 20 25 volts and 45 10 volts. internal solderless link adjustment. All other characteristics shall
