DLA MIL-PRF-26542 10 C-2012 MICROPHONE ASSEMBLY M-138 G.pdf

1、AMSC N/A FSC 5965 PERFORMANCE SPECIFICATION SHEET MICROPHONE ASSEMBLY, M-138/G This specification sheet is approved for use by all Departments and Agencies of the Department of Defense. The requirements for acquiring the product described herein shall consist of this specification sheet and MIL-PRF-

2、26542. FIGURE 1. Microphone assembly. MIL-PRF-26542/10C 12 September 2012 SUPERSEDING MIL-PRF-26542/10B 30 May 1997 INCH-POUND Inches mm .190 .203 .250 .375 .495 .516 1.125 2.125 11.750 4.83 5.16 6.35 9.53 12.57 13.11 28.58 53.98 298.45 Provided by IHSNot for ResaleNo reproduction or networking perm

3、itted without license from IHS-,-,-MIL-PRF-26542/10C 2 NOTES: 1. Dimensions are in inches. Tolerances are .015 inches, 2 degrees of angle, unless otherwise specified. 2. Quantity and configuration of sound apertures is optional. 3. Location of marking on surface shown is optional. 4. Set-screws shal

4、l hold the microphone securely to the cable assembly, be of slotted or Allen type, and recessed. 5. Metric equivalents are given for general information only and are based upon 1 inch = 25.4 mm. FIGURE 1. Microphone assembly - Continued. Frequency points (Hz) 300 600 1,400 2,300 3,000 3,500 7,000 Up

5、per Limits (dB) +4.0 +4.0 +4.0 +7.0 +7.0 +7.0 +1.0 Lower Limits (dB) -16.0 -4.0 -4.0 -4.0 -4.0 - - FIGURE 2. Frequency response. REQUIREMENTS: Component parts: Microphone element: Shall be in accordance with figure 1. Provided by IHSNot for ResaleNo reproduction or networking permitted without licen

6、se from IHS-,-,-MIL-PRF-26542/10C 3 Boom: Dimensions: Dimensions of the boom shall be in accordance with USAF Drawing 67B1854, for interchangeability with the next-higher-assembly. Color: Boom shall be the same color as the microphone element. Finish: Shall be in accordance with MIL-PRF-26542, title

7、d “Boom finish”. Operation: Shall be in accordance with MIL-PRF-26542, titled “Boom operating force”. Material: Shall be constructed from a high-strength, corrosion-resistant metal, meeting or exceeding the environmental and durability requirements of MIL-PRF-26542. Cable assembly: The cable assembl

8、y shall be Part or Identifying Number (PIN) M22442/38-1 in accordance with MIL-DTL-22442/38 and meet either requirement 1/ for interface to oxygen gear, interchangeability, and environmental performance. The microphone element shall provide a complete electrical and mechanical interface with the cab

9、le assembly. 1/ NOTE: The cable assembly shall meet the qualification requirements of MIL-DTL-22442, in accordance with the 2 (two) options as specified in the “Cable assemblies”, see MIL-PRF-26542. Plug assembly: U-173/U in accordance with USAF Drawing 57B12662 or electrically and mechanically comp

10、atible part, on microphone end, JJ-055 type in accordance with MIL-J-641/8, p/n M641/8-1 or equal on the free end. Performance: Sensitivity at ground level: -56 dBm at 1,000 Hz with an input SPL of 2.8 Pascals (28 dynes/cm2). “dBm” is the power ratio in decibels (dB) of the measured power referenced

11、 to one milliwatt (mW). Sensitivity at altitude: Sensitivity shall be within 3 dB relative to the ground level sensitivity, when altitude tested at 15,000 feet. Frequency response at ground level: Shall be in accordance with figure 2. The response curves generated shall be on the same scale as shown

12、 in figure 2. The response curve shall not exceed the upper and lower limit curves of the stationary Frequency Response Envelope, within the frequency ranges identified in the appropriate chart (see figure 2). Impedance: 150.0 ohms 15 ohms. Resistive load: 150.0 ohms. The microphone assembly shall b

13、e tested in accordance with the tests specified in table I. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-26542/10C 4 TABLE I. Parameter applicability. Inspection Qualification tests Group “A” tests Group “B” tests Group “C” tests Group I V

14、isual and mechanical inspection Sensitivity of ground level Sensitivity at altitude Frequency response at ground level Frequency response at altitude Impedance Noise cancellation characteristics Effect of external magnetic field Stray magnetic field Linearity Talk-out Dielectric withstanding voltage

15、 Signal-to-noise Distortion Interchangeability X X X X X X X X X X X X X X X X Group II Thermal shock Humidity Drop Pressure equalization Explosive decompression Salt fog X X X X X X X X Group III Vibration Bounce Altitude Moisture barrier seal Immersion X X X X X X X X Group IV Fungus X Group V Gun

16、 blast X Changes from previous issue. The margins of this specification are marked with vertical lines to indicate where changes from the previous issue were made. This was done as a convenience only and the Government assumes no liability whatsoever for any inaccuracies in these notations. Bidders

17、and contractors are cautioned to evaluate the requirements of this document based upon the entire content, regardless of the marginal notations and relationship to the last previous issue. Referenced documents. In addition to MIL-PRF-26542, this document references the following: USAF Drawing 57B126

18、62 USAF Drawing 67B1854 MIL-J-641/8 MIL-DTL-22442 MIL-DTL-22442/38 Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-26542/10C 5 CONCLUDING MATERIAL Custodians: Preparing activity: Army CR DLA - CC Navy EC Air Force 85 (Project 5965-2012-012) D

19、LA CC Review activities: Army AT, AV, CR4 Navy AS, OS Air Force 99 NOTE: The activities listed above were interested in this document as of the date of this document. Since organizations and responsibilities can change, you should verify the currency of the information above using the ASSIST Online database at https:/assist.dla.mil. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-