阅读说明：本技术 低阻抗送话器匹配低阻抗音频控制模块时的评价控制方法 (Evaluation control method for matching low-impedance microphone with low-impedance audio control module ) 是由 张艳玲 桑季 韦成业 周凤仪 彭华 于 2021-08-30 设计创作，主要内容包括：本发明公开了一种低阻抗送话器匹配低阻抗音频控制模块时的评价控制方法,选择五个评价指标并进行控制,五个评价分别为阻抗、灵敏度及频率响应、失真性能、指向性、面罩腔体结构。本发明保证了低阻抗送话器匹配低阻抗音频控制模块时的使用效果。(The invention discloses an evaluation control method for matching a low-impedance microphone with a low-impedance audio control module, which selects and controls five evaluation indexes, wherein the five evaluations are impedance, sensitivity, frequency response, distortion performance, directivity and a mask cavity structure respectively. The invention ensures the use effect of the low-impedance microphone matched with the low-impedance audio control module.)

1. An evaluation control method when a low-impedance microphone is matched with a low-impedance audio control module is characterized by comprising the following steps: five evaluation indexes are selected and controlled, and the method specifically comprises the following steps:

the first indicator is the impedance: designing the wire diameter and the winding number of turns of a microphone coil according to the low impedance requirement, and enabling the microphone coil to be in impedance matching with an audio control module at the rear end;

the second indicator is sensitivity and frequency response: the sensitivity determines the sound size of each frequency point, the frequency response of the whole frequency band determines the sound tone of the voice of the microphone, the voice voltage value required to be output by the low-impedance audio control module can reach 70mv to reach the saturation area of an AGC circuit of a radio station, the size and the stability of the voice signal received by a pilot can meet the requirements, the output voltage of the audio control module amplifies the input voltage by 140 times, because the energy of the voice signal received by the ears of the low-impedance microphone is mainly concentrated at 1000Hz, the sensitivity of the microphone at 1000Hz must be more than or equal to 0.5mv/Pa (-66dB/Pa), and meanwhile, in order to ensure the stability of the sound of the whole frequency band, the frequency response of the low-impedance microphone needs to be kept relatively stable at the voice frequency band of 200 plus 4000Hz, namely, the frequency response waveform is in a certain block diagram, and the fluctuation of the input voice signal is reduced;

the third indicator is distortion performance: the distortion performance determines the voice fidelity of the microphone, and the low-impedance microphone needs to evaluate the distortions of 200Hz, 500Hz, 1000Hz, 2000Hz and 4000Hz, so that the high fidelity is ensured in the whole frequency band;

the fourth index is directionality: the high-impedance transmitter only has higher requirement on directivity at 1000Hz and has low requirement on other frequencies, and the low-impedance transmitter has better directivity at 200Hz, 400 Hz, 800 Hz and 1000Hz, thereby ensuring the high anti-interference capability of the low-impedance transmitter;

the fifth criterion is in combination with the mask cavity structure: the pressure in the cabin changes during the flight process, after the microphone is arranged in the oxygen mask, the microphone is arranged in a closed cavity, the closed cavity is equivalent to a small reverberation field, when the air pressure in the mask changes, the frequency response characteristic of the microphone changes, and in order to debug better low-frequency response, the requirement on the damping of the rear cover with low impedance is high, the space of the rear cavity is small, the low impedance microphone also has emitted sound besides direct sound, the phase of reflected sound and multiple harmonics in the cavity of the mask is deflected after entering the microphone, thereby leading the electroacoustic performance of the microphone to change, and reducing the influence of the mask cavity on the rear cavity of the microphone when the low-impedance microphone is designed, when the microphone is designed, the microphone is provided with a certain back cavity, and the back cavity is quantitative, so that the influence of sound reflection and sound refraction generated by the back cavity of the mask on the microphone is reduced; meanwhile, a waterproof membrane is cancelled, so that the influence on the sound performance of the microphone when the air pressure changes is avoided.

2. The evaluation control method when the low impedance microphone is matched to the low impedance audio control module of claim 1, wherein: the low-impedance microphone comprises a closed cavity defined by an injection molding shell, a front cover damper and a rear cover damper, and an anti-interference coil, a voice coil voice diaphragm group, magnetic steel, a pole core and a moisture-proof film which are positioned in the closed cavity, wherein the voice coil voice diaphragm group is arranged in a uniform strong magnetic field, and when sound waves come, the voice diaphragm generates corresponding vibration to drive the voice coil to cut magnetic lines of force of the magnetic field to generate electromotive force; the size of the microphone is completely determined by the thickness and the number of turns of the anti-interference coil, the anti-interference coil is designed according to the low impedance size, the middle-high frequency 1000-4000 Hz response of the microphone is mainly determined by the front cover damping, the low frequency 200-1000 Hz response of the microphone is mainly determined by the rear cover damping, in order to enable the rear cover damping to reduce the influence of low air pressure on the microphone, the rear cavity of the microphone is quantitative, the influence of the cavity of the face mask on the sound reflection and the sound reflection of the cavity of the face mask is reduced, and meanwhile, the damp-proof film is thinned or canceled when no waterproof requirement exists.

Technical Field

The invention relates to a microphone, in particular to an evaluation control method for matching a low-impedance microphone with a low-impedance audio control module.

Background

At present, an audio control module matched with a combat aircraft is low-impedance, when the low-impedance microphone is designed according to GJB1773-1993 HK-91M type anti-noise microphone specification according to the design of a high-impedance microphone, the low-impedance microphone is matched with a pressurizing oxygen supply mask to fly, when the flying distance is long, ground tower duty personnel receive mask voice signals and have high noise, and meanwhile, when a pilot receives self-listening sound, the sound is low, so that the great trouble is brought to the communication of the pilot.

The GJB1773-1993 specification HK-91M anti-noise microphone specifies the technical index system of the high-impedance microphone, and specifies the impedance and sensitivity according to the impedance, frequency spectrum, distortion and directivity. However, the low-impedance microphone has low impedance and sensitivity, and is easily affected by the back-end audio control module, and the low-impedance microphone is designed according to the GJB1773-1993 HK-91M anti-noise microphone specification, which easily causes distortion of the microphone, so that the voice signal acquired by the back-end audio control module is too small and generates noise, therefore, the low-impedance microphone needs to be researched to determine the index system of the low-impedance microphone, so that the low-impedance microphone is matched with the back-end audio control module.

Disclosure of Invention

The invention aims to provide an evaluation control method when a low-impedance microphone is matched with a low-impedance audio control module, so that the use effect when the low-impedance microphone is matched with the low-impedance audio control module is ensured.

The technical scheme adopted by the invention is as follows:

an evaluation control method when a low-impedance microphone is matched with a low-impedance audio control module selects and controls five evaluation indexes, and specifically comprises the following steps:

the first indicator is the impedance: designing the wire diameter and the winding number of turns of a microphone coil according to the low impedance requirement, and enabling the microphone coil to be in impedance matching with an audio control module at the rear end;

the second indicator is sensitivity and frequency response: the sensitivity determines the sound of each frequency point, the frequency response of the whole frequency band determines the sound tone of the transmitter, the voice voltage value required to be output by the low-impedance audio control module must reach 70mv to reach the saturation area of the AGC circuit of the station, the size and the stability of the voice signal received by a pilot can meet the requirements, the output voltage of the audio control module amplifies the input voltage by 140 times, because the energy of the voice signal received by the ears of the low-impedance transmitter is mainly concentrated at 1000Hz, therefore, the sensitivity of the transmitter 1000Hz must be more than or equal to 0.5mv/Pa (-66dB/Pa), and simultaneously, in order to ensure the stability of the sound of the whole frequency band, the frequency response of the transmitter needs to be kept relatively stable in the voice frequency band (200 and 4000 Hz), namely, the frequency response waveform should be in a certain block diagram (the frequency response block diagram refers to the range of the up-down fluctuation of the sensitivity of the transmitter relative to 1000 Hz), reducing fluctuations in the input speech signal;

the third indicator is distortion performance: the distortion performance determines the voice fidelity of the microphone, and the low-impedance microphone needs to evaluate the distortions of 200Hz, 500Hz, 1000Hz, 2000Hz and 4000Hz, so that the high fidelity is ensured in the whole frequency band;

the fourth index is directionality: the high-impedance transmitter only has higher requirement on directivity at 1000Hz and has low requirement on other frequencies, and the low-impedance transmitter has better directivity at 200Hz, 400 Hz, 800 Hz and 1000Hz, thereby ensuring the high anti-interference capability of the low-impedance transmitter;

the fifth criterion is in combination with the mask cavity structure: the air pressure in the cabin changes in the flying process, after the microphone is arranged in the oxygen mask, the microphone is arranged in a closed cavity, the closed cavity is equivalent to a small reverberation field, when the air pressure in the mask changes, the frequency response characteristic of the microphone changes, in order to debug better low-frequency response, the requirement on the damping of a rear cover of a low impedance is high, the space of a rear cavity is small, the low impedance microphone has transmitting sound besides direct sound, reflected sound and multiple harmonics in the cavity of the mask enter the microphone, the phase deflects, the electroacoustic performance of the microphone changes, when the low impedance microphone is designed, the influence of the cavity of the mask on the rear cavity of the microphone is reduced, namely when the microphone is designed, the rear cavity of the microphone is quantitative as much as possible, and the influence of sound reflection and sound refraction on the rear cavity of the mask is reduced; meanwhile, a waterproof membrane is cancelled, so that the influence on the sound performance of the microphone when the air pressure changes is avoided.

Furthermore, the low-impedance microphone comprises a closed cavity surrounded by the injection molding shell, the front cover damper and the rear cover damper, and an anti-interference coil, a voice coil voice diaphragm set, magnetic steel, a pole core and a moisture-proof film which are positioned in the closed cavity, wherein the voice coil voice diaphragm set is arranged in a uniform strong magnetic field, and when sound waves come, the voice diaphragm vibrates correspondingly to drive the voice coil to cut magnetic lines of force of the magnetic field to generate electromotive force; the thickness and the number of turns of the anti-interference coil completely determine the size of the microphone, the anti-interference coil is designed according to the low impedance size, the front cover damping mainly determines the medium-high frequency 1000-4000 Hz response of the microphone, the rear cover damping mainly determines the low frequency 200-1000 Hz response of the microphone, and in order to enable the rear cover damping to reduce the influence of low air pressure on the microphone, the damp-proof membrane is thinned and designed or is cancelled when no waterproof requirement exists.

The invention has the beneficial effects that:

in order to solve the problem of noise of long-distance communication, the method considers the influence of air pressure change in a cabin and audio signal modulation and demodulation distortion of an audio control module on the performance of a microphone, establishes an index system of the low-impedance microphone, selects five evaluation indexes and controls the evaluation indexes, and ensures the use effect of the low-impedance microphone matched with the low-impedance audio control module.

Drawings

Fig. 1 is a schematic structural diagram of a microphone in an embodiment of the present invention.

Fig. 2 is a schematic diagram of the frequency response of a high impedance and low impedance microphone.

Fig. 3 is a schematic view of the directional characteristic of the microphone.

Fig. 4 is a microphone directivity diagram.

In the figure: 1-an anti-interference coil; 2-front cover damping; 3-voice coil voice diaphragm group; 4-injection molding the shell; 5-rear cover damping; 6-magnetic steel; 7-pole core; 8-moisture-proof film.

Detailed Description

The invention is further described below with reference to the figures and examples.

An evaluation control method when a low-impedance microphone is matched with a low-impedance audio control module selects and controls five evaluation indexes, and specifically comprises the following steps:

the first indicator is the impedance: designing the wire diameter and the winding number of turns of a microphone coil according to the low impedance requirement, and enabling the microphone coil to be in impedance matching with an audio control module at the rear end;

as shown in fig. 1, the low impedance microphone comprises a closed cavity surrounded by an injection molding shell 4, a front cover damper 2 and a rear cover damper 5, and an anti-interference coil 1, a voice coil voice diaphragm group 3, magnetic steel 6, a pole core 7 and a moisture-proof film 8 which are positioned in the closed cavity, wherein the voice coil voice diaphragm group 3 is arranged in a uniform strong magnetic field, and when sound waves come, the voice diaphragm generates corresponding vibration to drive the voice coil to cut magnetic lines of force of the magnetic field to generate electromotive force; the size of the microphone is completely determined by the thickness and the number of turns of the anti-interference coil 1, the anti-interference coil 1 is designed according to the low impedance, the front cover damper 2 mainly determines the medium-high frequency 1000-4000 Hz response of the microphone, the rear cover damper 5 mainly determines the low frequency 200-1000 Hz response of the microphone, and in order to enable the rear cover damper 5 to reduce the influence of low air pressure on the microphone, the damp-proof film 8 is thinned or canceled when no waterproof requirement exists.

The second indicator is sensitivity and frequency response: the sensitivity and the frequency response determine the voice timbre of the microphone, the energy of receiving voice signals by human ears is mainly concentrated on 1000Hz, the low-impedance microphone is easily influenced by a rear-end audio control module, the average sensitivity of 200-4000Hz is regulated besides the requirement on the sensitivity of 1000Hz, and meanwhile, in order to ensure that the fluctuation of the voice signals in the whole voice frequency band is small, the frequency response of the low-impedance microphone is required to be kept relatively stable in the voice frequency band of 200-4000 Hz;

as shown in fig. 2, according to the specification of GJB1773-1993 specification of HK-91M anti-noise microphone, the frequency response of the high-impedance microphone is defined as a + B, but the low-impedance microphone is to ensure the smoothness of the voice signal, and the frequency response is defined in the a region to ensure that the frequency response of the microphone fluctuates little.

The third indicator is distortion performance: the distortion performance determines the voice fidelity of the microphone, and the low-impedance microphone needs to examine the distortions of 200Hz, 500Hz, 1000Hz, 2000Hz and 4000Hz, so that the high fidelity is ensured in the whole frequency band.

The fourth index is directionality: the high-impedance transmitter only has higher requirement on directivity at 1000Hz and has low requirement on other frequencies, and the low-impedance transmitter has better directivity at 200Hz, 400 Hz, 800 Hz and 1000Hz, thereby ensuring the high anti-interference capability of the low-impedance transmitter;

as shown in fig. 3 and 4, when the normal of the receiving surface is perpendicular to the sound propagation, the sensitivity of the microphone is minimum, and the directivity of the microphone is 8, so that the microphone has better anti-noise performance.

The fifth criterion is mask cavity structure: the pressure in the cabin changes during the flight process, after the microphone is arranged in the oxygen mask, the microphone is arranged in a closed cavity, the closed cavity is equivalent to a small reverberation field, when the air pressure in the mask changes, the frequency response characteristic of the microphone changes, and in order to debug better low-frequency response, the requirement on the damping of the rear cover with low impedance is high, the space of the rear cavity is small, the low impedance microphone also has emitted sound besides direct sound, the phase of reflected sound and multiple harmonics in the cavity of the mask is deflected after entering the microphone, thereby leading the electroacoustic performance of the microphone to change, when the low-impedance microphone is designed, the design of the mask cavity is combined, on the basis of meeting other performances, certain back cavity and consistency of the back cavity of the microphone are required to be ensured, so that the performance of the microphone is not influenced when the air pressure changes.

In order to solve the problem of noise of long-distance communication, the method considers the influence of air pressure change in a cabin and audio signal modulation and demodulation distortion of an audio control module on the performance of a microphone, establishes an index system of the low-impedance microphone, selects five evaluation indexes and controls the evaluation indexes, and ensures the use effect of the low-impedance microphone matched with the low-impedance audio control module.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.