General specification for air-conduction dynamic and electro magnetic transmitters
Some standard content:
Military standard of the electronics industry of the People's Republic of China FL5965
SJ20045—92
General specification for air-condnctiondynamic and electro magnetic transmitters Issued on February 1, 1992
China Electronics Industry Corporation Implemented on May 1, 1992 1 Scope Military standard of the electronics industry of the People's Republic of China General specification for air-condnctiondynamic and electromagnetic transmitters 1.1 Subject content
SJ20045-92
This specification specifies the technical requirements and quality assurance provisions for military air-condnctiondynamic and electro magnetic transmitters. 1.2 Scope of application
This specification applies to dynamic and electromagnetic microphones for wired and wireless communications of the Army, Navy and Air Force (hereinafter referred to as microphones). 2 Referenced documents
The valid versions of the following documents constitute a part of this specification within the scope specified in this specification. GJB179
SJ20128
SJ20368
3 Requirements
3.1 Detailed specifications
Counting sampling inspection procedures and tables
Environmental test methods for communication electroacoustic devices
Methods for measuring the performance of microphones and receivers
Specific product requirements shall comply with this specification and be specified by detailed specifications. If the requirements of this specification and detailed specifications are inconsistent, the detailed specifications shall prevail.
3.2 Qualification appraisal
Products submitted in accordance with this specification shall be qualified products or approved by finalization. 3.3 Materials
All materials used in the product shall comply with the provisions of this specification. If some materials are not specified, when using those materials, it shall be ensured that the microphone meets the performance requirements specified in this specification. The acceptance or approval of any material of the product shall not be used as the basis for the acceptance of the product.
3.3.1 Unqualified materials
Natural rubber or natural rubber adhesive shall not be used in microphones. 3.3.2 Diaphragm materials
The diaphragm material shall be metal or plastic.
3.3.3 Adhesives and adhesives
The adhesives used in the microphone shall maintain sufficient bonding strength and shall not produce other adverse effects. The use of water-soluble adhesives issued by China Electronics Industry Corporation on February 1, 1992 and implemented on May 1, 1992 is not allowed.
3.4 Design and structure
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The design of the microphone shall be carried out in accordance with the provisions of this specification and detailed specifications, and its mechanical and acoustic characteristics shall be very stable to ensure the interchangeability of the product.
3.4.1 Pressure balance
When the external atmospheric pressure drops to 10kPa, the pressure inside and outside the microphone diaphragm shall remain balanced. 3.4.2 Mass
Unless otherwise specified, the maximum mass of the microphone shall not exceed 48g. 3.4.3 Explosion decompression
The stability of the diaphragm material and the concentricity of the voice coil and the air gap shall not be affected by explosion decompression. 3.4.4 Moisture-proof layer
The microphone shall have a moisture-proof layer to prevent moisture from entering. 3.4.5 Surface coating
The surface coating shall comply with the requirements of the technical documents. 3.5 Performance requirements
3.5.1 Sensitivity
3.5.1.1 The sensitivity of the microphone on the ground shall comply with the provisions of the detailed specifications. 3.5.1.2 The deviation of the sensitivity of the microphone for high altitude in the simulated 7500m altitude environment relative to the sensitivity on the ground shall not exceed ±3dB.
3.5.2 Frequency response
3.5.2.1 The frequency response of the microphone on the ground shall comply with the provisions of the detailed specifications. 3.5.2.2 The deviation of the frequency response of the microphone for high altitude in the simulated 7500m altitude environment relative to the frequency response on the ground shall not exceed ±3dB.
3.5.3 Impedance
The impedance value and tolerance of the microphone at 1000Hz shall comply with the provisions of the detailed specifications, and the tolerance shall be selected from the following specified values:
The impedance tolerance of the dynamic microphone shall not exceed ±15%b, and the impedance tolerance of the electromagnetic microphone shall not exceed ±30%. 3.5.4 Total Harmonic Distortion
At any frequency point within the specified effective frequency, when the input sound pressure of the microphone is 94dB or 124dB (the reference sound pressure is 2X10-5Pa), the total harmonic distortion value at the output end shall comply with the provisions of 3.5.4.1 to 3.5.4.3. 3.5.4.1 When the input sound pressure is 94dB:
The total harmonic distortion of the dynamic microphone shall not exceed 3%; a.
b, the total harmonic distortion of the electromagnetic microphone shall not exceed 5%. 3.5.4.2 When the input sound pressure level is 124dB: the total harmonic distortion of the animated microphone shall not exceed 6%; a.
the total harmonic distortion of the electromagnetic microphone shall not exceed 10%. 3.5.4.3 The total harmonic distortion of the anti-noise microphone shall comply with the provisions of the detailed specifications. 3.5.5 Signal-to-noise ratio
The signal-to-noise ratio of various types of anti-noise microphones shall be selected from the following specified values: 2
18dB.
3.5.6 Leakage magnetic field
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The leakage magnetic field of the microphone shall not cause a 5° deviation of the compass at a distance of 30cm from it. 3.5.7 The influence of external magnetic field on the microphone
The sensitivity of the microphone in an external magnetic field of 400Hz shall not be greater than 25% of the sensitivity of the standard coil placed in the same magnetic field.
3.5.8 Linearity
: In the effective frequency range of 200～4000Hz, when the input sound pressure level is 84, 94, 104, 114dB, the output voltage of the microphone is a linear function of its input sound pressure (the reference sound pressure is 2×10-5Pa), and its deviation shall comply with the provisions of the detailed specification. 3.5.9 Withstand voltage
When the microphone is subjected to a withstand voltage test of 500V, 50Hz AC for 1min, there shall be no arcing or breakdown between the connector and the non-conductive part.
3.6 Environmental test requirements
The environmental test items and test categories that the microphone needs to withstand shall be specified in the detailed specification in accordance with the requirements of 3.6.1~3.6.10.
3.6.1 Vibration
After the microphone is subjected to the vibration test specified in Table 1, there shall be no structural damage or other adverse effects, and the change in frequency response relative to the initial value shall not exceed ±3dB. Vibration test requirements
3.6.2 Damp heat
Frequency range
10~55~10
10~55~10
Amplitude
One scan time
Test time
After the microphone is subjected to the damp heat test specified in Table 2, the change in its frequency response relative to the initial value shall not exceed ±3dB, and the withstand voltage shall meet the requirements of Article 3.5.9.
Table 2 Damp heat test requirements
3.6.3 High temperature
+30~+60
+30~+60
Relative humidity
Test time
After the microphone is subjected to the high temperature test specified in Table 3, the change in its frequency response relative to the initial value shall not exceed ±3dB. 3
3.6.4 Low temperature
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Table 3 High temperature test requirements
Test temperature
Test time
After the microphone is subjected to the low temperature test specified in Table 4, the change in frequency response relative to the initial value should not exceed ±3dB. Table 4 Low temperature test requirements
3.6.5 Low pressure
Test temperature
Test time
After the microphone is subjected to the low pressure test specified in Table 5, the change in frequency response relative to the initial value should not exceed ±3dB. Table 5 Low pressure test requirements
3.6.6 Temperature shock
Corresponding altitude
Test temperature
+15~+35
+15～+35
Test time
After the microphone is subjected to the temperature shock test specified in Table 6, the change in frequency response relative to the initial value should not exceed ±3dB. Table 6 Temperature shock test requirements
3.6.7 Shock
Test temperature
-55→+85
Number of shock cycles
After the microphone is subjected to the shock test specified in Table 8, there should be no cracking, deformation, or looseness that can cause failure. Minor indentations and scratches can be ignored. The change in frequency response relative to the initial value should not exceed ±3dB. Table 7, shock test requirements
Acceleration
Pulse duration
Total number of shocks
Shock waveform
Half-sine waveform
Half-sine waveform
3.6.8 Drop
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After the microphone is subjected to the drop test specified in Table 8, there should be no cracking, deformation, or looseness that can cause failure. Minor indentations and scratches can be ignored. The change in frequency response relative to the initial value should not exceed ±3dB. Table 8 Drop test requirements
3.6.9 Salt spray
Drop height
Number of drops
After the microphone is subjected to the salt spray test specified in Table 9, its surface should not be corroded. The change of frequency response relative to the initial value should not exceed ±3dB. The withstand voltage should meet the requirements of Article 3.5.9. Table 9 Salt spray test requirements
Salt solution
3.6.10 Bacteria
Salt spray sedimentation rate
ml/80cm*.h
(Take the average value of more than 16h
)
Test temperature
Salt spray treatment method
Spray for 24h, dry for 24h under normal test atmospheric conditions
, which constitutes a cycle.
Continuous spray
Test time
After the microphone is subjected to the sterilization test specified in Article 11.3 of SJ20128 "Environmental test methods for communication electroacoustic devices", there should be no bacterial growth, and the change of its frequency response relative to the initial value should not exceed ±3dB. 3.7 Marking
The microphone should be marked according to the following items. All marks should be clear, obvious, and not easy to wear. If the microphone surface area is too small to be marked, other corresponding symbols should be used and explained in the detailed specifications. The marking should include the following:
Trademark;
Model:
Specification:
Inspection pass stamp;
Factory date.
3.8 Appearance quality
The microphone should be well surface treated to ensure the appearance quality. The microphone should be free of burrs, surface peeling and cracks.
4 Quality Assurance Provisions
4.1 Inspection Responsibilities
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Unless otherwise specified in the contract or order, the manufacturer shall be responsible for completing all inspections specified in this specification. When necessary, the ordering party or the supervision and inspection agency has the right to inspect any inspection items specified in this specification. 4.1.1 Responsibility for Conformity
The products must meet all requirements specified in Chapter 3 and Chapter 5 of this specification. The inspections specified in this specification shall become an integral part of the manufacturer's entire inspection system or quality program. If the contract includes inspection requirements not specified in this specification, the manufacturer shall also ensure that the products submitted for acceptance meet the contract requirements. Quality consistency inspection sampling does not allow the submission of products that are known to be defective, nor can the ordering party be required to accept defective products. 4.1.2 Test instruments and test equipment
In order to complete the required inspection items, the manufacturer shall set up devices to ensure that the test equipment has sufficient accuracy, quality and quantity.
4.2 Test conditions
4.2.1 Atmospheric conditions
Unless otherwise specified, all tests specified in this specification shall be carried out under the following normal test atmospheric conditions: temperature: +15+35℃, relative humidity: 20%~80%; pressure: 86~106kPa.
4.2.2 Acoustic conditions
Unless otherwise specified, the acoustic measurement conditions in this specification shall comply with the requirements of SJ20368 "Methods for measuring the performance of transmitters and receivers".
4.3 Classification of tests
The tests specified in this specification are divided into:
8. Appraisal test,
b. Quality consistency test.
4.4 Appraisal test
Appraisal test shall be carried out in the laboratory designated by the supervision and inspection agency. 4.4.1 Sample size
If no fungal test is conducted, 6 microphones shall be submitted for identification inspection. Otherwise, 9 microphone samples shall be submitted. 4.4.2 Inspection rules
Samples shall be inspected in the order specified in Table 10. All samples must be inspected in Group 1 and then divided into two groups (three groups when there is a fungal test) and then inspected in Group 2, Group 3 and Group 4 respectively. Table 10 Identification test
Test content
Group 1
Appearance and mechanical inspection
Sensitivity
Frequency response
Total harmonic distortion
Requirement clause
3.1, 3.3, 3.4, 3.7, 3.8
Method clause
Test content
Signal-to-noise ratio
Irrigation magnetic field
Influence of external magnetic field on microphone
Group 2
Group 3
Low air pressure
Temperature shock
Group 4
4.4.3 Failure
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Continued Table 10
Requirement clause
If one failure occurs, the identification test will fail. 4.4.4 Retention of qualification
Method clause
To retain the qualification, the manufacturer shall submit an application report to the supervision and inspection agency every 12 months, and the supervision and inspection agency shall determine the date of report submission. The report content shall include the following two parts: a. The results of product delivery inspection (i.e. Group A and Group B inspection) expressed in the number of qualified batches and the number of failed batches. The inspection results of the repair batches must be identified and explained.
b. Periodic inspection (i.e. Group C inspection) result report. If the test results in the report are inconsistent with the requirements of this specification or detailed specifications, and no improvement measures are taken, the qualification of the product shall be cancelled from the qualified product catalog. If there is no product within the period of submitting the report, a report can be submitted to explain that there is still the ability and necessary equipment to carry out the work, or it can be handled according to the opinions of the supervision and inspection agency. 4.5 Quality consistency inspection
4.5.1 Product delivery inspection
Product delivery inspection shall include Group A and Group B inspection. 4.5.1.1 Inspection batch
The same inspection batch shall include all microphones of the same model produced under the same conditions and submitted for inspection at the same time.
4.5.1.2 Group A inspection
Group A inspection includes the items in the order specified in Table 11. a.
Sampling plan:
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The sampling plan shall be in accordance with GJB179, general inspection level 1, and the acceptable quality level (AQL) shall be in accordance with Table 11. The defect classification for appearance and mechanical inspection is shown in Table 14. Table 11 Group A inspection
Inspection content
Appearance and mechanical inspection
Spiritual education
Yan rate response
b. Rejected batch:
Requirement clause
3.1.3.3,3.4.
Method clause
Non-conforming products
Non-conforming products
If an inspection batch is rejected, the manufacturer shall correct its failure or screen out the failed products and resubmit for inspection. The resubmitted batch shall be subject to stricter inspection. Such batches shall be distinguished from new batches and clearly marked as resubmitted batches. 4.5.1.3 Group B inspection
Group B inspection shall include the inspection items specified in Table 12, and the samples that have passed the Group A inspection shall be inspected. Sampling plan:
The sampling plan shall be in accordance with the special inspection level S-4 in GJB179. The size of the sample shall be determined by the inspection lot of Group A inspection, and the acceptable quality level (AQL) shall comply with the provisions of Table 12. Table 12 Group B inspection
Inspection content
Total harmonic distortion
Signal-to-noise ratio
Rejected batch
Requirement clause
Method clause
If an inspection lot is rejected, the manufacturer shall correct its failure or screen out the failed products and resubmit it for inspection. The resubmitted batch shall be subject to stricter inspection. Such a batch shall be distinguished from the new batch and clearly marked as a resubmitted batch. c. Sample processing:
If the inspection lot is qualified and the sample performance is within the specified tolerance range, the samples that pass the Group B inspection can be delivered according to the contract or order of the ordering party.
4.5.2 Periodic inspection
Periodic inspection shall be carried out according to Group C inspection. Unless Group C inspection fails, products that have passed Group A and Group B inspections shall not be delayed in delivery due to unclear results of periodic inspection. 4.5.2.1 Group C inspection
Group C inspection shall include the inspections specified in Table 13, and samples for Group C inspection shall be taken from qualified batches that have passed Group A and Group B inspections.
a. Sampling plan:
Group C inspection shall be carried out every 6 months, with a sample size of 6. 8
b. Failure:
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As long as one failure occurs, the batch of products will fail Group C inspection. Table 13 Group C inspection
Inspection content
Temperature shock
Low pressure
c. Sample handling:
Requirement clause
Method clause
Samples that have passed the Group C inspection shall not be delivered as qualified products according to the contract or order. d. Handling of unqualified batches:
Number of samples
If a batch of products fails to pass the Group C inspection, the acceptance and delivery of the products shall be stopped. The manufacturer shall report the unqualified situation to the supervision and inspection agency. After taking improvement measures, the manufacturer shall re-inspect all or only inspect the unqualified items according to the opinions of the supervision and inspection agency. If the inspection is still unqualified, the unqualified situation shall be reported to the supervision and inspection agency and the qualification of the product shall be cancelled.
4.5.3 Packaging inspection
The sampling and inspection of packaging (including inner packaging and outer packaging) shall comply with the provisions of the detailed product specifications. 4.6 Inspection and test methods
4.6.1 Appearance and mechanical inspection
The quality, dimensions, marking and appearance quality of the microphone shall be inspected according to the corresponding requirements (see 3.1.3.3, 3.4, 3.7, 3.8). The defect classification is shown in Table 14. 4.6.2 Sensitivity
According to 5.1.6 of SJ20368 "Methods for measuring the performance of microphones and receivers". 4.6.3 Frequency response
According to 5.1.7 of SJ20368 "Methods for measuring the performance of microphones and receivers". 4.6.4 Impedance
"According to 5.1.4 of SJ20368 "Measurement Method for Microphone and Receiver Performance". 4.6.5 Total Harmonic Distortion
According to 5.1.14 of SJ20368 "Measurement Method for Microphone and Receiver Performance". 4.6.6 Signal-to-Noise Ratio
According to 5.1.13 of SJ20368 "Measurement Method for Microphone and Receiver Performance". 4.6.7 Hysteresis Magnetic Field
According to 5.1.20 of SJ20368 "Measurement Method for Microphone and Receiver Performance". 4.6.8 Effect of External Magnetic Field on Receiver
According to 5.1.19 of SJ20368 "Measurement Method for Microphone and Receiver Performance". 4.6.9 Linearity
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Perform according to Article 5.1.9 of SJ20368 "Methods for measuring the performance of microphones and receivers". 4.6.10 Withstand voltage
Perform according to Article 5.1.17 of SJ20368 "Methods for measuring the performance of microphones and receivers". The test voltage should be applied between one output terminal of the microphone and the metal parts or other metal surfaces not covered with insulating materials. After the test, it should meet the requirements of Article 3.5.9. 4.6.11 Vibration
Perform according to Article 9.3 of SJ20128 "Environmental Test Methods for Communication Electroacoustic Devices". The following contents should be followed: a. Installation method: The microphone should be installed horizontally with the front end exposed. b. Final measurement: Measure the frequency response according to Article 4.6.3, and the result should meet the requirements of Article 3.6.1. 4.6.12 Wet Heat
Perform according to Article 10.3 and 10.4 of SJ20128 "Environmental Test Methods for Electroacoustic Devices in Communications", and the following contents should be followed: a. Installation: The microphone should be installed vertically with the front end exposed. b. Final measurement: After the microphone is restored, measure the frequency response according to Article 4.6.3, and check the withstand voltage according to Article 4.6.10. The result should meet the requirements of Article 3.6.2.
4.6.13 High temperature
Perform according to Article 5.3 of SJ20128 "Environmental Test Methods for Electroacoustic Devices in Communications", and the following contents should be followed: a. Installation: The microphone should be installed vertically with the front end exposed. b. Final measurement: After the microphone is restored, measure the frequency response according to Article 4.6.3, and the result should meet the requirements of Article 3.6.3.
4.6.14 Low temperature| |tt||According to Article 4.3 of SJ20128 "Environmental Test Methods for Electroacoustic Devices for Communication", the following contents should be followed: Installation method: The microphone should be installed vertically with the front end exposed. a.bzxz.net
Final measurement: After the microphone is restored, the pre-frequency response should be measured according to Article 4.6.3, and the result should meet the requirements of Article 3.6.4 b.
5 Low pressure
According to Article 6.3 of SJ20128 "Environmental Test Methods for Electroacoustic Devices for Communication", after the test, the frequency response should be measured according to Article 4.6.3. The result should meet the requirements of Article 3.6.5. 4.6.16 Temperature shock
According to Article 7.3 of SJ20128 "Environmental Test Methods for Electroacoustic Devices for Communication", the following contents should be followed a. Installation method: The microphone should be installed vertically with the front end exposed. b.Final measurement: The frequency response should be measured according to Article 4.6.3, and the result should meet the requirements of Article 3.6.6. 4.6.17 Impact
Perform according to 8.3 of SJ20128 "Environmental Test Methods for Electroacoustic Devices in Communications", and the following contents should be followed: a. Installation method: The microphone should be firmly installed on the surface of the impact table, and the diaphragm should be kept vertical to the table surface. b. Final measurement: Measure the frequency response according to 4.6.3, and the result should meet the requirements of 3.6.7. 4.6.18 Fall
Perform according to 13.3 of SJ20128 "Environmental Test Methods for Electroacoustic Devices in Communications", and the following contents should be followed: a. Installation method: The microphone should be installed vertically with the front end exposed. b. Final measurement: After the microphone is restored, check the appearance according to 4.6.1 and measure the frequency response according to 4.6.3, and the result should meet the requirements of 3.6.8.
4.6.19 Salt spray
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According to 12.3 of SJ20128 "Environmental test methods for communication electroacoustic devices", the following contents should be followed: a. Installation method: The microphone should be installed vertically with the front end exposed. b. Final measurement: The microphone should be cleaned and restored according to the instructions. Within 3 hours after drying, the frequency response and withstand voltage should be measured according to 4.6.3 and 4.6.10. The results should meet the requirements of 3.6.9. 4.6.20 Jiang Jun
According to 11.3 of SI20128 "Environmental test methods for communication electroacoustic devices", the following contents should be followed: a. Installation method: The microphone should be installed vertically with the front end exposed. Final measurement: After the microphone is restored for 1 hour, check the mold growth according to S]20128 Communication Electroacoustic Device Environmental Test Method b.
, and measure the frequency response according to Article 4.6.3. The result should meet the requirements of Article 3.6.10. Table 14 Defect classification of appearance and mechanical inspection No.
Inspection content
Materials and surfaces
Materials do not meet the requirements. Wrong or incomplete surface treatment
Parts and components
Dimensions
5 Delivery preparation
5.1 Packaging
General, large amount of peeling or breaking of the surface. Missing or wrongly installed parts, and assembly of unqualified parts make the microphone inoperable.
Marking is missing, wrong or the handwriting is illegible. Any loosely attached metal foreign matter causes a short circuit or abnormal sound of the microphone.
Any non-metallic foreign matter (such as insulating material, dirt, etc.) causes the microphone to sound abnormal.
Solder leaks, cold solder joints or insufficient solder (less than twice the diameter).
The size exceeds the allowable deviation specified in the detailed specification, affecting interchangeability.
The surface has scratches, wear, etc. that expose the bottom metal, or there is a small amount of flaking or peeling.
Unqualified parts are assembled, but the function is not affected.
The logo color is not bright or has stains, but it is recognizable.
Any metallic or non-metallic foreign matter affects the appearance, but will not cause the microphone to sound abnormal and the function is not affected.
The size exceeds the allowable deviation specified in the detailed specification, but will not affect interchangeability.
The microphone should be cleaned, dried, sealed and inner packaged according to the provisions of the detailed specification before packing. 5.2 Packing
Microphones with inner packaging should be packed according to the specifications of the products. The same packing box can only hold products of the same specifications and be accompanied by a quality inspection certificate. The packing box should be weather-resistant and should avoid resonance during transportation. 5.3 Transportation and storage
The well-packed transmitter should be suitable for various modes of transportation, including land, sea and air. The product should be stored in a warehouse with an ambient temperature of -10 to +35°C and a relative humidity of no more than 80%. The surrounding air should not contain acidic, alkaline and other corrosive gases.
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