阅读说明：本技术 防啸叫电声通话装置 (Anti-squeal electroacoustic calling device ) 是由 李祥伟 宋韫峥 杭彪 于 2020-02-17 设计创作，主要内容包括：本发明提供了一种防啸叫电声通话装置,包括：壳体部件、线路板单元、拾音器部件、扬声器部件；所述壳体部件包括：第一壳体部件、第二壳体部件；所述拾音器部件与第一壳体部件相连；所述扬声器部件设置于第二壳体部件上；所述线路板单元设置于第一壳体部件与第二壳体部件所形成的空间内；所述线路板单元包括：运放电路；所述运放电路包括：滑动电阻器RP1、电阻R2、电阻R3、电阻R4、电容C5、电解电容C6、电解电容C7、声音信号输入端以及声音信号输出端；本发明时结构合理,使用方便,能够克服现有技术中的缺陷。(The invention provides a howling-preventing electroacoustic calling device, which comprises: a housing part, a circuit board unit, a sound pickup part, and a speaker part; the housing member includes: a first housing member, a second housing member; the sound pick-up component is connected with the first shell component; the loudspeaker part is arranged on the second shell part; the circuit board unit is arranged in a space formed by the first shell part and the second shell part; the wiring board unit includes: an operational amplifier circuit; the operational amplifier circuit includes: a slide resistor RP1, a resistor R2, a resistor R3, a resistor R4, a capacitor C5, an electrolytic capacitor C6, an electrolytic capacitor C7, a sound signal input end and a sound signal output end; the invention has reasonable structure and convenient use, and can overcome the defects in the prior art.)

1. A howling-preventing electroacoustic conversation device, comprising: a housing part, a circuit board unit, a sound pickup part, and a speaker part;

the housing member includes: a first housing member, a second housing member;

the sound pick-up component is connected with the first shell component;

the loudspeaker part is arranged on the second shell part;

the circuit board unit is arranged in a space formed by the first shell part and the second shell part;

the wiring board unit includes: an operational amplifier circuit;

the operational amplifier circuit includes: a slide resistor RP1, a resistor R2, a resistor R3, a resistor R4, a capacitor C5, an electrolytic capacitor C6, an electrolytic capacitor C7, a sound signal input end and a sound signal output end;

the sound signal input end is respectively connected with one end of the resistor R2, one end of the capacitor C5 and the ground wire;

the other end of the resistor R2 is connected with a power supply;

the other end of the capacitor C5 is connected with one end of a resistor R3;

the other end of the resistor R3 is connected with one end of a resistor R4 and a fourth pin of the L M4871 chip;

the other end of the resistor R4 is connected with the fixed end of a sliding resistor RP 1;

the sliding end of the sliding resistor RP1 is connected with the sound signal output end;

the anode of the electrolytic capacitor C6 is connected with the second pin and the third pin of the L M4871 chip;

the cathode of the electrolytic capacitor C6 is connected with the first pin and the ground wire of the L M4871 chip;

the first pin of the L M4871 chip is connected with a ground wire;

the fifth pin and the eighth pin of the L M4871 chip are connected with a sound signal output end;

the sixth pin of the L M4871 chip and the anode of the electrolytic capacitor C7 are connected with a power supply;

and the negative electrode of the electrolytic capacitor C7 is connected with the ground wire.

2. The howling-resistant electro-acoustic conversation device according to claim 1, wherein said microphone means employs a directional anti-interference electret microphone;

one end of the directional anti-interference electret microphone is grounded;

the other end of the directional anti-interference electret microphone is connected with one end of a resistor R2.

3. The howling-preventing electro-acoustic conversation device according to claim 1, wherein the speaker part is a speaker;

the resistance of the loudspeaker is 8 omega;

the power of the loudspeaker is 1W;

the diameter of the loudspeaker is 50 mm;

the sliding end of the sliding resistor RP1 and the fifth pin of the L M4871 chip are connected with one end of a loudspeaker;

the eighth pin of the L M4871 chip is connected to the other end of the speaker.

4. The howling-preventing electro-acoustic conversation device according to claim 1, further comprising: a switch member;

the switch component is connected with the second shell component;

the switch component is connected with the operational amplifier circuit.

5. The anti-howling electro-acoustic conversation device according to claim 1, wherein a capacitance value of the capacitor C5 is obtained by using a calculation formula:

Ci＝1/(2ΠRiFi)；

wherein Ci is a filter capacitor; ri is a configured gain resistor; fi is the pronunciation frequency.

6. A howling-preventing electroacoustic conversation device, comprising: a housing part, a circuit board unit, a sound pickup part, and a speaker part;

the housing member includes: a first housing member, a second housing member;

the sound pick-up component is connected with the first shell component;

the loudspeaker part is arranged on the second shell part;

the circuit board unit is arranged in a space formed by the first shell part and the second shell part;

the wiring board unit includes: an operational amplifier circuit;

the operational amplifier circuit includes: a slide resistor RP1, a resistor R2, a resistor R3, a resistor R4, a capacitor C5, an electrolytic capacitor C6, an electrolytic capacitor C7, a sound signal input end and a sound signal output end;

the sound signal input end is respectively connected with one end of the resistor R2, one end of the capacitor C5 and the ground wire;

the other end of the resistor R2 is connected with a power supply;

the other end of the capacitor C5 is connected with one end of a resistor R3;

the other end of the resistor R3 is connected with one end of a resistor R4 and a fourth pin of the L M4871 chip;

the other end of the resistor R4 is connected with the fixed end of a sliding resistor RP 1;

the sliding end of the sliding resistor RP1 is connected with the sound signal output end;

the anode of the electrolytic capacitor C6 is connected with the second pin and the third pin of the L M4871 chip;

the cathode of the electrolytic capacitor C6 is connected with the first pin and the ground wire of the L M4871 chip;

the first pin of the L M4871 chip is connected with a ground wire;

the fifth pin and the eighth pin of the L M4871 chip are connected with a sound signal output end;

the sixth pin of the L M4871 chip and the anode of the electrolytic capacitor C7 are connected with a power supply;

the negative electrode of the electrolytic capacitor C7 is connected with the ground wire;

the sound pick-up part adopts a directional anti-interference electret microphone;

one end of the directional anti-interference electret microphone is grounded;

the other end of the directional anti-interference electret microphone is connected with one end of a resistor R2;

the loudspeaker component adopts a loudspeaker;

the resistance of the loudspeaker is 8 omega;

the power of the loudspeaker is 1W;

the diameter of the loudspeaker is 50 mm;

the sliding end of the sliding resistor RP1 and the fifth pin of the L M4871 chip are connected with one end of a loudspeaker;

the eighth pin of the L M4871 chip is connected to the other end of the speaker;

further comprising: a switch member;

the switch component is connected with the second shell component;

the switch component is connected with the operational amplifier circuit;

the capacitance value of the capacitor C5 is obtained by adopting the following calculation formula:

Ci＝1/(2ΠRiFi)；

wherein Ci is a filter capacitor; ri is a configured gain resistor; fi is the pronunciation frequency.

Technical Field

The invention relates to the field of electroacoustic public address systems, in particular to a howling-preventing electroacoustic communication device, and particularly relates to a small-sized integrated electroacoustic public address system.

Background

The electroacoustic interphone is combined with the gas mask for use, is suitable for personnel wearing the gas mask to execute combat missions, compensates attenuation of voice pressure level and speech definition caused by a gas mask cavity and a communication membrane when performing exercise training and handling emergencies, and can remarkably enhance voice communication capacity after the personnel wear the electroacoustic interphone. After the gas mask is worn, the voice communication is carried out with adjacent players, and due to the sealing and isolating effect of the gas mask, the speaking voice is shielded, and the adjacent players cannot clearly hear the speaking voice; in addition, the electroacoustic interphone is installed on the gas mask, is small in size, is close to the installation positions of the microphone and the loudspeaker, and is easy to generate howling.

Patent document CN204272379U discloses a gas mask electroacoustic communicator, which comprises a main body and a sound pick-up, wherein the main body is buckled on the outer side of the front end of the gas mask, the sound pick-up is arranged on the inner side of the front end of the gas mask, and the sound pick-up is connected with a sending socket; the main body consists of a shell, a loudspeaker, a battery and a circuit board, wherein the loudspeaker, the battery and the circuit board are arranged in the shell; a transmitting plug is arranged on the rear end face of the shell and is connected with a transmitting socket; the circuit board is provided with a signal processor and an audio power amplifier, the input end of the signal processor is connected with the transmitting plug, the output end of the signal processor is connected with the input end of the audio power amplifier, and the output end of the audio power amplifier is connected with the loudspeaker; the lower part of the shell is provided with an expiration passage, the inlet end of the expiration passage corresponds to the exit of an expiration valve at the front end of the gas mask, and the outlet end is positioned below the shell. The patent still has room for improvement in the prevention of howling and sound amplification of the electro-acoustic calling device.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a howling-preventing electroacoustic calling device.

The squeal-proof electroacoustic calling device comprises a housing part, a circuit board unit, a pickup part and a loudspeaker part, wherein the housing part comprises a first housing part and a second housing part, the pickup part is connected with the first housing part, the loudspeaker part is arranged on the second housing part, the circuit board unit is arranged in a space formed by the first housing part and the second housing part, the circuit board unit comprises an operational amplifier circuit, the operational amplifier circuit comprises a sliding resistor RP1, a resistor R2, a resistor R3, a resistor R4, a capacitor C5, an electrolytic capacitor C6, an electrolytic capacitor C7, an audio signal input end and an audio signal output end, the audio signal input end is respectively connected with one end of the resistor R2, one end of the capacitor C5 and the ground wire, the other end of the resistor R2 is connected with a power supply, the other end of the capacitor C9 is connected with one end of the resistor R3, the other end of the resistor R3 is connected with one end of the resistor R4, one end of the capacitor C5 and the ground wire, the fourth pin of the chip 4871, the other end of the resistor R68672 is connected with the anode pin of the anode pin 368672, the anode pin of the anode pin 6 and the cathode pin of the anode pin 6 of the anode pin of the capacitor R4875 is connected with the anode pin 6 of the anode pin 364875 of the anode pin 36487 of the anode pin 6, the anode pin 6 of the anode pin 36487 of the anode pin 6, the anode pin 6 of the anode pin 364875 of the anode pin 6 and the anode pin 6 of.

Preferably, the sound pick-up component adopts a directional anti-interference electret microphone; one end of the directional anti-interference electret microphone is grounded; the other end of the directional anti-interference electret microphone is connected with one end of a resistor R2.

Preferably, the loudspeaker component is a loudspeaker, the resistance of the loudspeaker is 8 omega, the power of the loudspeaker is 1W, the diameter of the loudspeaker is 50mm, the sliding end of the sliding resistor RP1 and the fifth pin of the L M4871 chip are connected with one end of the loudspeaker, and the eighth pin of the L M4871 chip is connected with the other end of the loudspeaker.

Preferably, the method further comprises the following steps: a switch member; the switch component is connected with the second shell component; the switch component is connected with the operational amplifier circuit.

Preferably, the capacitance value of the capacitor C5 is obtained by the following calculation formula: ci ═ 1/(2 Π RiFi); wherein Ci is a filter capacitor; ri is a configured gain resistor; fi is the pronunciation frequency.

Compared with the prior art, the invention has the following beneficial effects:

1. the microphone adopts the directional anti-interference electret microphone, the microphone has strong directivity, only the signal from the right front can generate a strong signal on the microphone, and the signals in other directions are very weak, so that self-excited howling is avoided;

2. the circuit of the invention adopts a filter circuit to filter out clutter, and carries out the calculation design of sound transmission loss, nonlinear distortion and signal-to-noise ratio during design, thereby avoiding the distortion of sound.

Drawings

Other features, objects and advantages of the invention will become more apparent upon reading of the detailed description of non-limiting embodiments with reference to the following drawings:

fig. 1 is a schematic diagram of an operational amplifier circuit used in the present invention.

Fig. 2 is a schematic diagram of the principle framework of the present invention.

Fig. 3 is a schematic diagram of a relationship between a filter capacitor and a response frequency according to an embodiment of the invention.

Fig. 4 is a schematic diagram of the relationship between the frequency and the THD + N in the embodiment of the present invention.

Detailed Description

The present invention will be described in detail with reference to specific examples. The following examples will assist those skilled in the art in further understanding the invention, but are not intended to limit the invention in any way. It should be noted that it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the spirit of the invention. All falling within the scope of the present invention.

As shown in fig. 1-4, the whistling prevention electroacoustic calling device provided by the invention comprises a housing part, a circuit board unit, a microphone part and a loudspeaker part, wherein the housing part comprises a first housing part and a second housing part, the microphone part is connected with the first housing part, the loudspeaker part is arranged on the second housing part, the circuit board unit is arranged in a space formed by the first housing part and the second housing part, the circuit board unit comprises an operational amplifier circuit, the operational amplifier circuit comprises a sliding resistor RP1, a resistor R2, a resistor R3, a resistor R4, a capacitor C5, an electrolytic capacitor C6, an electrolytic capacitor C7, a sound signal input end and a sound signal output end, the sound signal input end is respectively connected with one end of the resistor R2, one end of the capacitor C5 and a ground wire, the other end of the resistor R2 is connected with a power supply, the other end of the capacitor C5 is connected with one end of a resistor R3, the other end of the resistor R3 is connected with one end of the resistor R4, one end of the capacitor C5 and the ground wire, the other end of the resistor R861 is connected with a power supply pin 6, the other end of the anode pin of the sliding resistor R4871 is connected with the anode pin 6, the anode pin of the anode pin 6 is connected with the anode pin of the anode pin 6C 4875, the anode pin 6 of the anode pin 6, the anode pin 6 of the anode pin 6, the anode pin of the anode pin 36487 chip 487 is connected with the anode pin 6, the cathode pin 6.

Preferably, the sound pick-up component adopts a directional anti-interference electret microphone; one end of the directional anti-interference electret microphone is grounded; the other end of the directional anti-interference electret microphone is connected with one end of a resistor R2.

Preferably, the loudspeaker component is a loudspeaker, the resistance of the loudspeaker is 8 omega, the power of the loudspeaker is 1W, the diameter of the loudspeaker is 50mm, the sliding end of the sliding resistor RP1 and the fifth pin of the L M4871 chip are connected with one end of the loudspeaker, and the eighth pin of the L M4871 chip is connected with the other end of the loudspeaker.

Preferably, the method further comprises the following steps: a switch member; the switch component is connected with the second shell component; the switch component is connected with the operational amplifier circuit.

Preferably, the capacitance value of the capacitor C5 is obtained by the following calculation formula: ci ═ 1/(2 Π RiFi); wherein Ci is a filter capacitor; ri is a configured gain resistor; fi is the pronunciation frequency.

Therefore, noise can be effectively filtered by selecting a proper filter capacitor, and the signal-to-noise ratio is improved. The relationship of the response frequency for different filter capacitances can also be seen in fig. 3.

The main circuit adopts a bridge type audio power amplifier, the power supply voltage is 3V, the amplitude limit of the output of the amplifier is 3V, when the sound input is large and the amplification gain is also large, the output of the amplifier exceeds 3V, but the amplitude limit exists, so the distortion can be generated under the condition. Therefore, a suitable magnification (8 times magnification) is selected.

The amplification gain value is calculated by the formula:

R_f/R_i＝A_VD/2 (3)

the larger the gain, the higher the volume, but too much volume easily causes nonlinear distortion. In general, the gain is about 4-5 times, and the sound effect is the best.

The PN loudspeaker has the advantages of small volume, large sound, bright tone quality, natural and smooth property, distinct gradation and anti-interference performance. Considering matching with the operational amplifier, an output load typical value is selected: 8 omega 1W.

In the case of an amplifier with an output load of 8 Ω 1W and a gain of 5, the total harmonic distortion plus noise (THD + N) is about 0.25%. The electro-acoustic talker system shown in fig. 4 can satisfy the excellent non-linear loss and snr performance.

The electroacoustic interphone adopts low-noise components and reasonable filter circuits to eliminate power supply fluctuation, and simultaneously carries out reasonable wiring and grounding on audio input and output. A core component in the audio amplification circuit selects an audio power amplification module, the input end selects a directional anti-interference electret microphone, the microphone is strong in directivity, only signals coming from the front can generate strong signals on the microphone, signals in other directions are weak, and self-excitation squeaking is avoided. The output end adopts an 8 omega 1W loudspeaker with the diameter of 50 mm. 2-section No. 7 mercury-free alkaline dry batteries are adopted for power supply, so that the replacement and maintenance are convenient. The schematic diagram of the circuit is shown in fig. 1.

The unity gain can be adjusted by adjusting the slide rheostat RP 1. The larger the gain factor, the louder the sound, but too loud will cause distortion. Through high-pass filtering, low-frequency clutter can be filtered out, and the output audio sound effect is higher.

The microphone adopts the directional anti-interference electret microphone, the microphone has strong directivity, only the signal from the right front can generate a strong signal on the microphone, and the signals in other directions are very weak, so that self-excited howling is avoided; the circuit of the invention adopts a filter circuit to filter out clutter, and carries out the calculation design of sound transmission loss, nonlinear distortion and signal-to-noise ratio during design, thereby avoiding the distortion of sound.

Those skilled in the art will appreciate that, in addition to implementing the system and its various devices, modules, units provided by the present invention as pure computer readable program code, the system and its various devices, modules, units provided by the present invention can be fully implemented by logically programming method steps in the form of logic gates, switches, application specific integrated circuits, programmable logic controllers, embedded microcontrollers and the like. Therefore, the system and various devices, modules and units thereof provided by the invention can be regarded as a hardware component, and the devices, modules and units included in the system for realizing various functions can also be regarded as structures in the hardware component; means, modules, units for performing the various functions may also be regarded as structures within both software modules and hardware components for performing the method.

In the description of the present application, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present application and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present application.

The foregoing description of specific embodiments of the present invention has been presented. It is to be understood that the present invention is not limited to the specific embodiments described above, and that various changes or modifications may be made by one skilled in the art within the scope of the appended claims without departing from the spirit of the invention. The embodiments and features of the embodiments of the present application may be combined with each other arbitrarily without conflict.