1、VIL-PRF-624BA 0b 204b207 5T7 = -1 MIL-PRF-6248 8A( AT) 25 July 1997 SUPERSEDING 28 August 1985 MIL-A-62488(AT) PERFORMANCE SPECIFICATION AMPLIFIER, AUDIO FREQUENCY This speciication is approved for use by U.S. Army Tank-automotive and Armaments Command, Department of the Army, and is available for u
2、se by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers an audio frequency amplifier (hereafter referred to as a distribution unit) used on military ground vehicles. 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are s
3、pecified in sections 3 and 4 of this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned t
4、hat they must meet all specified requirement documents cited in sections 3 and 4 of this specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications. standards, and handbooks. The following specifications, standards, and handbooks form a part of this document to the
5、 extent specified herein. Unless otherwise specified, the issues of these documents are those listed in the issue of the Department of Defense Index of Specifications and Standards (DoDISS) and supplement thereto, cited in the solicitation (see 6.2). Beneficial comments (recommendations, additions,
6、deletions) and any pertinent data which may be of use in improving this document should be addressed to: U.S. Army Tank-automotive and Armaments Command, ATTN: AMSTA-TR-EBLUE, Warren, MI 48397-5000, by using the Standardization Document Improvement Proposal (DD Form 1426) appearing at the end of thi
7、s document, or by letter. AMSC NA FSC 5820 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- MIL-PRF-62488A W 9999906 2046208 433 MIL-PRF-6248 8A(AT) STANDARDS DEPARTMEN
8、T OF DEFENSE MIL-STD-462 MIL-STD-810 - Measurement of Electromagnetic Interference Characteristics, Test Method Standard for. - Environmental Test Methods and Engineering Guidelines. (Unless otherwise indicated, copies of the above specifications, standards, and handbooks are available from the Stan
9、dardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19 1 1 1-5094 .) 2.2.2 Other Government documents. drawings. and Dubfications. The following other Government documents, drawings, and publications form a part of this document to the extent specified herein. Unless o
10、therwise specified, the issues are those cited in the solicitation. DRAWINGS ARMY 123 10227 - Amplifier, Audio Frequency (Interface). (Copies of these drawings are available from the U.S. Army Tank-automotive and Armaments Command, ATTN: AMSTA-TR-E/BLUE, Warren, MI 48397-5000,) 2.3 Non-Government Du
11、blications. The following document(s) form a part of this document to the extent specied herein. Unless otherwise specified, the issues of the documents which are DoD adopted are those listed in the issue of the DoDISS cited in f? solicitation. Unless otherwise specified, the issues of documents not
12、 listed in the DoDISS are the issues of the documents cited in the solicitation (see 6.2). AMERICAN NATIONAL STANDARD INSTITUTE (ANSI) ANSWASQC Z1.4 ANSVSAEi AS478 - Sampling Procedures and Tables for Inspection by - Identification Marking Methods OD Adopted). Attributes OD Adopted). (Application fo
13、r copies should be addressed to American National Standard Institute, 11 West 42nd Street, New York, NY 10036.) 2 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- NIL-PRF-bZ4BBA 9999906 2046209 37T MIL-PRF-6248 8A( AT) AMERICAN SOCIETY FOR TESTING AN
14、D MATERIALS (ASTM) ASTM D522 ASTM D5487 - Standard Test Methods for Mandrel Bend Test of - Standard Test Method for Simulated Drop of Loaded Attached Organic Coatings OD Adopted). Containers by Shock Machines. (Application for copies should be addressed to the American Society for Testing and Materi
15、als, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959.) 2.4 Order of precedence. In the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulati
16、ons unless a specific exemption has been obtained. 3. REQUIREMENTS 3.1 First article. When specified (see 6.2), a sample shall be subjected to first article inspection in accordance with 4.3. 3.2 Materials. Materials used shall be in accordance with the manufacturers materials specification for audi
17、o amplifiers. The materials shall be capable of meeting all the operational and environmental requirements specified herein (see 4.5.1). 3.2.1 Recvcled. recovered. or environmentally preferable materials. Recycled, recovered, or environmentally preferable materials should be used to the maximum exte
18、nt possible provided that the material meets or exceeds the operational and maintenance requirements, and promotes economically advantageous life cycle costs. 3.2.2 FunPus proof materials. To the greatest extent practical, the materials used in the distribution unit shall be non-nutrients for fungi.
19、 If materials that are nutrients for fungi must be utilized, such materials shall be approved by the Government (see 4.5.1). 3.2.3 Potting compounds. Potting compounds employed in the distribution unit shall meet all of the environmental requirements specified herein without adversely affecting the
20、performance of the distribution unit (see 4.5.1). 3.2.4 Insulating compounds. The electrical coating for printed circuit assemblies shall meet all of the environmental requirements specified herein without adversely affecting the performance of the distribution unit (see 4.5.1). 3 Provided by IHSNot
21、 for ResaleNo reproduction or networking permitted without license from IHS-,-,- - MIL-PRF-62488A 9Ob 2046230 O93 W MIL-PRF-624 8 8A(AT) 3.2.5 Metal parts. All ferrous metal parts shall be of corrosion resistant type or treated to provide corrosion protection and coating adherence equal to or exceed
22、ing that provided by hot dip galvanized 1010 steel with a minimum coating thickness of 50 micrometers (2 ds) on steel sheet less than 1.6 millimeters (mm) C0.0625 inches (in.) thick, 64 micrometers (2.5 ds) on steel sheet greater than 1.6 mm (0.0625 in.) thick or 19 micrometers (0.75 mils) on pregal
23、vanized steel sheet 1.6 mm (0.0625 in.) thick or less. A material sample shall be capable of meeting or exceeding the corrosion resistance provided by a galvanized sample (as described above) when subjected to the mandrel bend test of ASTM D522. Suitable protection against dissimilar metals and galv
24、anic corrosion shali be provided. Magnesium shall not be used unless specifically authorized (see 4.5.1). 3.2.6 Non-metallic parts. Non-metallic parts shall be designed to minimize deterioration caused by exposure to sunlight, sand particles, microorganisms, moisture, temperature extremes, fuel, hyd
25、raulic and lubricating oil, grease, and salt degradation associated with abrasion, load, or exposure-induced deterioration that can endanger or jeopardize the hnction of the system (see 4.5.1). 3.3 Design and construction. The distribution unit shall be fabricated and assembled in accordance with th
26、e manufacturers design and construction for distribution units, except for envelope dimensions, mounting dimensions and locations, and electrical mounting interfaces as shown in Drawing 12310227 and as specified herein (see 4.4.2,4.5.1, and 4.5.2). 3.3.1 Size and weight. The distribution unit shall
27、be 24.8 centimeters (cm) (9.75 in.) long by 14.6 cm (5.75 in.) wide by 9.5 cm (3.75 in.) deep. The weight of the distribution unit shall not exceed 3.6 kilograms (kg) 8 pounds (lbs) (see 4.5.2 and 4.5.3). 3.3.2 Controls and interfaces. 3.3.2.1 Interface description. The distribution unit shall inter
28、face with a variety of audio accessories, radio sets (receive-transmit), receivers (radio receive only), and field wire line. Primary interface details shall be as specified in figure 1. When radio sets are used with the intercom, they are connected to the distribution unit through J501,J503, J509 a
29、nd J511 receptacles. All four radio sets may be of the receive-transmit type. The retransmission function requires that two radio sets be connected to receptacles J501 and J503. This function serves as a radio relay to increase the range between these two external radio sets. When radio sets (receiv
30、e-transmit) are not used, direct current (dc) power for the intercom is supplied through receptacle J508. The radio output of an auxiliary receiver may be connected to the audio input binding posts to enable monitoring. This monitoring cannot be disabled by intercom controls. Field wire lines may be
31、 connected from a local battery telephone to the line binding posts to enable two-way communication between any crew member within reach of the distribution units LINEPRESS TO TALK pushbutton switch. Monitoring field wire line communications is automatic and cannot be disabled by intercom controls (
32、see 4.5.3). 4 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-UIL-PRF-62488A 9999906 2046231 T28 HELMET OTHER AUDIO ACCESSORIES I: MIL-PRF-624 8 8A(AT) 802) CREW UNIT CONTROL -OR- 803 I I I 80 1 802 I HELMET CREW CONTROL -0R- OTHER STATION TO f - CAB
33、LE EXTERNAL POWER SOURCE WHEN NOT CONNECETED TO RADIO SET 8031 AUDIO ACCESSORIES HELMET cvc I CREW -dl OZR 803,mE tgp AUDIO ACCESSORIES i I zl CREW - AUDIO ACCESSORIES however, it shall not be possible for any crew control unit to initiate a radio transmission on the radios connected to J501 or 5503
34、 when in the RETRANSMISSION mode (see 4.5.3). 3.3.3 Interface Darts. All interface parts shall be in accordance with Drawing 123 10227 (see 4.5.1). * 3.4 Performance. 3.4.1 SuDplv range. The distribution unit shall operate within specifications over a supply voltage range of 20 to 30 volts (V) dc. T
35、he dc power requirement shall not exceed 20 watts (W) at 26 V dc. The distribution unit shall not be damaged by operation from a supply operating at worst case limits the following conditions (see 4.5.4.1). 3.4.1.1 Steady-state voltage. Circuit steady-state voltage shall be between 25 and 30 V for c
36、ombined generator-battery power supply, 20 to 27 V for battery only condition and no less than 33 V for generator only condition. 8 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-6248 8A(AT) 3.4.1.2 Ripple. Upper and lower peaks of ripple vo
37、ltage (see figure 3) shall each be less than 2 V for combined generator-battery power supply and battery only power condition and 7 V for generator only condition. The frequency components of the ripple shall be within the range of 50 Hertz (Hz) to 200 kilohertz (kHz). 3.4.1.3 Surges. All surges res
38、ulting from system operation shall fall within the loci shown in figure 4 for combined generator-battery power supply and in figure 5 for generator only condition. For battery only condition, any switching activity resulting in a surge which takes the voltage outside steady-state limits will be cons
39、idered as a fault condition for the duration of the excursion. 3.4.1.4 Spikes. All spikes resulting from system operation shali fall within the loci shown in figure 6 for combined generator-battery power supply and battery only condition and in figure 5 for generator only condition. 3.4.2 Radio rece
40、ive audio input impedance. The input impedance between pins A and K of J501,5503, J509 and J5 1 1 shall be 150 ohms the gain from pins A and K of J509 to pin T of J504, J505, J506 and J507; and the gain from pins A and K of J511 to pin S of J504, J505, J506 and J507 shall also be 417 5 23 mV per V w
41、hen measured at 1000 Hz (see 4.5.4.3). 3.4.4 Radio receive freauency response. With a 0.22 V root mean square (rms) signal applied at the fiequencies listed below, the output voltage shall be as specified below (see 4.5.4.4): Freauencv (Hz) Output level (mV) 150 8+3 300 80.5 $r 20 1000 91.7 It 5 350
42、0 97.9 t 2.2 5000 98.3 t 2.2 3.4.5 Radio receive distortion. The radio receive buffer shall perform as specified with a 0.22 V rms input at pin K of J501, J503, J509 and J511 with less than 2% total harmonic distortion (thd) when measured at 1000 Hz (see 4.5.4.5). 9 Provided by IHSNot for ResaleNo r
43、eproduction or networking permitted without license from IHS-,-,-3.4.6 Radio receive crosstalk. The output from any non-driven radio buffer shall be at least 50 decibels (dB) below the output of a driven radio buffer channel (see 4.5.4.6). 3.4.7 Radio receive buffer output impedance. The output impe
44、dance between pins J, M, T and S and pin A of J504, J505, J506 and 5507 shall be 46 ohms 2 10% each when measured at 1000 Hz (see 4.5.4.7). 3.4.8 Intercom accent control. The intercom accent control shall reduce the output of the radio receive buffers 20 5 3 dB when activated (see 4.5.4.8). 3.4.9 Mi
45、crophone buffer audio input imPedance. The input impedance between pins K, N, U and V and pin A of 5504, J505, J506 and J507 shall be 68 ohms ph N of 5504, J505,5506 and 5507 to pin U of 1503; pin U of J504, J505, 5506 and J507 to pin U of J509; and pin V of 5504, J505, J506 and J507 to pin U of 551
46、1 shallbe 11.86+0.8 VperV(see4.5.4.10). 3.4.1 1 Microphone buffer frequency response. The microphone buffer frequency response shall be flat t 2 dB from 300 to 3500 Hz (see 4.5.4.11). 3.4.12 Microphone buffer distortion. The microphone buffer shall perform as specified with a 35 mV, 1000 Hz signal a
47、pplied at the input. The output shall contain less than 2% thd (see 4.5.4.12). 3.4.13 Microphone buffer crosstalk. *The output from any non-driven microphone buffer shall be at least 50 dB below the output of a driven microphone buffer (see 4.5.4.13). 3.4.14 Microphone buffer output impedance. The o
48、utput impedance between pins U and A of J501, J503, J509 and J511 shall be 150 ohms + 10% each when measured at 1000 Hz (see 4.5.4.14). 3.4.15 Retransmit gain. With the retransmit switch on RETRANS, the voltage gah fi-om pin K of J501 to pin U of 5503 and from pin K of J503 to pin U of J501 shd be 2
49、.01 2 0.5 V per V when measured at 1000 Hz (see 4.5.4.15). 3.4.16 Line amplifier inmt impedance. The input impedance at the line terminals when measured at 1000 Hz shall be 600 ohms + 10% balanced, when in the LISTEN mode (see 4.5.4.16). 10 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,- MIL-PRF-62488A 9999906 2046217 446 MIL-PRF-624 8 8A( AT) 3.4.17 Lin
