A corded microphone that eliminates current sound

Abstract

This invention provides a wired microphone for eliminating current noise, comprising a microphone housing, a metal shield and a microphone circuit inside the microphone housing, the metal shield being detachably connected to the microphone housing, and forming a shielding cavity within the metal shield to omnidirectionally shield external electromagnetic interference; the microphone circuit includes a field-effect transistor Q1 located within the shielding cavity. This invention has the advantages of saving on microphone material costs while eliminating current noise.

Description

Technical Field

[0001] This utility model relates to the technical field of acoustic products, and in particular to a wired microphone that eliminates electrical noise. Background Technology

[0002] A microphone is a device that converts sound waves into electrical signals. It is widely used in audio recording, broadcasting, communication, and public speaking, primarily for capturing and transmitting sound. Its working principle is based on acoustics, enabling it to accurately reproduce sound details. Wired microphones, in particular, connect directly to audio equipment via cables, making them less susceptible to radio interference or signal loss during transmission, thus leading to their widespread use.

[0003] Existing microphones include a microphone tube containing a circuit board and a microphone capsule electrically connected to the circuit board. A field-effect transistor (FET) is soldered onto the circuit board. One end of the microphone tube is the pickup end, with the microphone capsule positioned close to it. In use, the microphone is connected to an audio playback device (such as a speaker). The user holds the microphone tube, allowing the pickup end to capture sound, which is then processed by the FET and the circuit board before being played back through the audio playback device.

[0004] If, in an effort to save on microphone material costs, the microphone tube is not made entirely of metal or is only partially made of metal, a noticeable hum will be produced when the microphone is used and placed on a table. This is because electrostatic interference and electromagnetic noise are directly coupled into the audio circuit through the non-metallic parts of the casing. At the same time, the table becomes a conductive medium, inducing AC ripple on the signal ground line. Since the field-effect transistor (FET) is highly susceptible to interference, the interfered FET is the main cause of the hum.

[0005] To address the above pain points, the industry urgently needs to develop a wired microphone that can eliminate hum while saving on microphone material costs. Utility Model Content

[0006] In order to improve the problem of current noise caused by the material cost of existing microphones, this utility model provides a wired microphone that can save on the material cost of microphones while eliminating current noise.

[0007] This utility model provides a wired microphone that eliminates electrical noise, employing the following technical solution:

[0008] A wired microphone for eliminating current noise includes a microphone housing, a metal shield and a microphone circuit disposed inside the microphone housing, the metal shield being detachably connected to the microphone housing, and a shielding cavity forming inside the metal shield to shield external electromagnetic interference in all directions; the microphone circuit includes a field-effect transistor Q1, the field-effect transistor Q1 being located in the shielding cavity.

[0009] By adopting the above technical solution, the shielding cavity space is smaller, and the shielding is more comprehensive, enabling all-round shielding against external electromagnetic interference to the MOSFET Q1. Due to the operating performance of the MOSFET Q1, it is more susceptible to electromagnetic interference, which can easily lead to signal distortion or increased noise, a major cause of current hum. Protecting the MOSFET Q1 with a metal shield optimizes its operating environment. Furthermore, the metal shield allows the microphone housing to be made without metal, reducing costs while still achieving interference resistance and preventing current hum. Simultaneously, eliminating the need for an all-metal microphone housing reduces overall weight, improving ease of use and comfort, especially during extended use, reducing hand fatigue and enhancing the user experience.

[0010] Preferably, the metal shielding cover includes a shielding base with one end open and a shielding cover detachably connected to the shielding base; the shielding cover has a sound pickup hole and a metal mesh covering the sound pickup hole.

[0011] Preferably, the microphone housing includes a cup head and a tube body detachably connected to the cup head. The side wall of the cup head and the end opposite to the tube body are provided with sound holes. The inner wall of the cup head is provided with an internal thread, and the end of the tube body near the cup head is provided with an external thread. The internal thread and the external thread cooperate with each other.

[0012] Preferably, the outer wall of the shielding base is provided with an external thread, and the shielding cover is provided with an internal thread that is compatible with the shielding base.

[0013] Preferably, the shielding base is provided with an external thread three, and the inner side of the tube is provided with an internal thread three. The internal thread three and the external thread three cooperate with each other. When the metal shielding cover is connected to the tube body, the end of the metal shielding cover near the shielding cover is located inside the cup head.

[0014] Preferably, the shielding base has a wiring hole at the end opposite to the shielding cover, through which the power supply line passes.

[0015] Preferably, the microphone circuit further includes:

[0016] A microphone (MIC) is used to convert sound waves into audio signals, and the microphone is electrically connected to a field-effect transistor (FET) Q1.

[0017] A signal amplification module, which is electrically connected to the field-effect transistor Q1, is used to amplify audio signals;

[0018] A voltage regulator unit is electrically connected to the microphone and the signal amplification module. The voltage regulator unit is used to regulate the voltage of the microphone and the field-effect transistor Q1.

[0019] The connector is electrically connected to the signal amplification module and is used to output audio signals.

[0020] Preferably, the microphone (MIC) is located in the shielding cavity, and the shielding base is provided with a support portion, which is just enough to place the microphone and bring the microphone close to the metal mesh.

[0021] Preferably, the signal amplification module includes a circuit board and an amplification unit disposed on the circuit board. The amplification unit is used for signal amplification, signal splitting and balanced output. The amplification unit is electrically connected to the field-effect transistor Q1 and the connector.

[0022] Preferably, the amplification unit includes a secondary amplification section, a non-inverting amplification section, and an inverting amplification section; the secondary amplification section is electrically connected to the field-effect transistor Q1, and the secondary amplification section is used to amplify audio signals; the non-inverting amplification section is electrically connected to the secondary amplification section, and the non-inverting amplification section is used to amplify and output a non-inverting output signal to the connector; the inverting amplification section is electrically connected to the secondary amplification section, and the inverting amplification section is used to amplify and generate an inverting output signal to the connector.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The shielding cavity is smaller and provides more comprehensive shielding, effectively blocking external electromagnetic interference to the MOSFET Q1. Due to the MOSFET Q1's operating characteristics, it is more susceptible to electromagnetic interference, which can easily lead to signal distortion or increased noise, a major cause of current noise. Protecting the MOSFET Q1 with a metal shield optimizes its operating environment. Furthermore, the metal shield allows the microphone housing to be made without metal, reducing costs and providing anti-interference and preventing current noise.

[0025] 2. The microphone circuit, through the coordinated work of voltage regulation, signal amplification, and output modules, can stably amplify and output high-quality audio signals, making it suitable for professional recording environments and further reducing the generation of current noise. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a cross-sectional view of the overall structure of the microphone described in this embodiment of the utility model.

[0028] Figure 2 yes Figure 1 Enlarged image.

[0029] Figure 3 This is a schematic diagram showing the relationship between the field-effect transistor Q1 and the microphone in an embodiment of this utility model.

[0030] Figure 4 This is a logic diagram of the microphone circuit in an embodiment of this utility model.

[0031] Figure 5 This is a circuit diagram of the microphone circuit in an embodiment of this utility model.

[0032] Figure 6 This is a circuit diagram of the signal amplification module in an embodiment of this utility model.

[0033] Figure 7 This is a circuit diagram of the voltage regulator unit in an embodiment of this utility model.

[0034] The component designations are as follows: 1. Microphone housing; 11. Cup head; 12. Tube body; 2. Metal shielding cover; 21. Shielding base; 22. Shielding cover; 3. Microphone circuit; 31. Field effect transistor Q1; 32. Microphone capsule (MIC); 33. Signal amplification module; 331. Circuit board; 332. Secondary amplification section; 333. Non-phase amplification section; 334. Inverting amplification section; 34. Voltage regulator unit; 35. Connector; 4. Shielding cavity; 5. Pickup hole; 6. Metal mesh; 7. Sound passage hole; 8. Internal thread one; 9. External thread one; 10. External thread two; 13. Internal thread two; 14. External thread three; 15. Internal thread three; 16. Line hole; 17. Stand; 18. Pickup slot; 19. Mounting cavity. Detailed Implementation

[0035] The following will refer to the appendix in the embodiments of this utility model. Figures 1 to 7The technical solutions in the embodiments of this utility model are clearly and completely described herein. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0036] A wired microphone for eliminating hum includes a microphone housing 1, which includes a cup head 11 and a tube 12 detachably connected to the cup head 11. The cup head 11 is a hollow cylinder with a pickup groove 18 at one end, which is also circular. Several circular, circular sound holes 7 are provided on the sidewalls of the cup head 11 and at the end opposite to the tube 12, communicating with the pickup groove 18 and the outside of the cup head 11. The tube 12 is a gradually tapering cylindrical tube, tapering from near the cup head 11 to away from it, forming a mounting cavity 19 within the tube 12.

[0037] The inner wall of the cup head 11 has an internal thread 8, and the end of the tube body 12 near the cup head 11 has an external thread 9. The internal thread 8 and the external thread 9 cooperate with each other, that is, the cup head 11 is threadedly connected to the tube body 12, realizing a detachable connection between the cup head 11 and the tube body 12. This allows the cup head 11 and the tube body 12 to be easily disassembled and connected, facilitating cleaning, maintenance, and replacement of parts. Furthermore, when the cup head 11 is threadedly connected to the tube body 12, the pickup groove 18 and the mounting cavity 19 are interconnected.

[0038] The microphone housing 1 contains a metal shield 2 and a microphone circuit 3. The metal shield 2 is detachably connected to the microphone housing 1. The metal shield 2 is made of aluminum alloy. Aluminum alloy has good conductivity, which can effectively block electromagnetic waves, avoid external electromagnetic interference, and prevent signal leakage inside the device, ensuring the stability and accuracy of signal transmission. In addition, aluminum alloy is relatively light, which can reduce the overall weight of the device. Furthermore, it has the advantages of strong corrosion resistance and good heat dissipation, making it suitable for microphone equipment.

[0039] The metal shield 2 includes a shielding base 21 with one end open and a shielding cover 22 detachably connected to the shielding base 21. In this embodiment, the shielding base 21 and the shielding cover 22 are threaded together. The outer wall of the shielding base 21 is provided with an external thread 10, which is close to the opening of the shielding base 21. The shielding cover 22 is provided with an internal thread 13 that is compatible with the shielding base 21, so as to facilitate opening or closing the metal shield 2. When the metal shield 2 is closed, a shielding cavity 4 that shields external electromagnetic interference in all directions is formed inside the metal shield 2.

[0040] The shielding base 21 of the metal shielding cover 2 is provided with an external thread 3 14, with one end of the external thread 3 14 close to the shielding base 21 and away from the external thread 2 10. An internal thread 3 15 is provided on the inner side of the tube body 12, and the internal thread 3 15 cooperates with the external thread 3 14, that is, the metal shielding cover 2 is threadedly connected to the tube body 12, realizing a detachable connection between the metal shielding cover 2 and the tube body 12. Furthermore, when the metal shielding cover 2 is connected to the tube body 12, the end of the metal shielding cover 2 near the shielding cover 22 is located within the pickup groove 18 of the cup head 11, facilitating sound pickup. This allows the metal shielding cover 2 to be easily fixed or removed from the microphone housing 1.

[0041] The shielding cover 22 has a circular pickup hole 5 that extends through the shielding cover 22. The shielding cover 22 is provided with a metal mesh 6 that covers the pickup hole 5. The mesh of the metal mesh 6 allows the interior of the metal shielding cover 2 to communicate with the pickup slot 18. The metal mesh 6 also shields against electromagnetic interference (EMI) and radio frequency interference (RFI) to prevent external electromagnetic waves from affecting the pickup effect.

[0042] Specifically, the microphone circuit 3 includes a microphone capsule (MIC) 32, a field-effect transistor (FET) Q131, a signal amplification module 33, a voltage regulator unit 34, and a connector 35. The microphone capsule (MIC) 32 converts sound waves into audio signals (AC signals). The FET Q131 amplifies the audio signal initially and converts the high-impedance audio signal into a low-impedance output; the FET Q131 is electrically connected to the microphone capsule (MIC) 32. The signal amplification module 33 is electrically connected to the FET Q131 and amplifies the audio signal. The voltage regulator unit 34 is electrically connected to both the microphone capsule (MIC) 32 and the signal amplification module 33, and it regulates the voltage of the microphone circuit 3. The connector 35 is used to output the audio signal.

[0043] Both the microphone MIC32 and the field-effect transistor Q131 are housed within the shielding cavity 4 of the metal shielding cover 2. The microphone MIC32 is a condenser microphone. A support 17 is provided within the shielding base 21, which is precisely positioned to house the microphone MIC32 and brings it close to the metal mesh 6. The support 17 helps to securely place the microphone MIC32, maintaining it in the appropriate position and ensuring a suitable distance between the microphone MIC32 and the metal mesh 6, thus facilitating better sound wave reception. The field-effect transistor Q131 is an N-channel junction field-effect transistor, also known as a FET, model K596S-C. The operating voltage of the field-effect transistor Q131 is 1.5V-6V. The field-effect transistor Q131 is located within the shielding base 21, on the side closest to the microphone MIC32.

[0044] Because the shielding cavity 4 inside the metal shielding cover 2 has a smaller space, the shielding is more comprehensive, effectively shielding the microphone MIC 32 and the field-effect transistor Q131 from external electromagnetic interference. Due to the operating performance of the field-effect transistor Q131, it is more susceptible to electromagnetic interference, which can easily lead to signal distortion or increased noise, a major cause of current noise. The metal shielding cover 2 protects the field-effect transistor Q131, ensuring its optimal operating environment. Therefore, even without using an all-metal material for the microphone head 11 and body 12 (saving on the cost of the microphone housing 1), interference resistance and prevention of current noise can still be achieved through the metal shielding cover 2. Furthermore, the elimination of the need for an all-metal microphone housing 1 reduces the overall weight of the microphone, improving ease of use and comfort, especially during extended use, reducing hand fatigue and enhancing the user experience.

[0045] The MIC+ output pin of the microphone MIC32 is electrically connected to the gate (G) of the field-effect transistor Q131, the source (S) of the field-effect transistor Q131 is grounded, and the drain (D) of the field-effect transistor Q131 is electrically connected to the signal amplification module 33. That is, the microphone converts sound waves into audio signals. The audio signal is input from the gate of the field-effect transistor Q131, undergoes preliminary signal amplification and impedance transformation by the field-effect transistor Q131 to reduce signal loading loss, and is then output from the drain of the field-effect transistor Q131 to the signal amplification module 33 for further processing.

[0046] In addition, a wiring hole 16 is provided at the end of the shielding base 21 away from the shielding cover 22. The power supply line passes through the wiring hole 16, and the wiring hole 16 connects the shielding groove and the mounting cavity 19. The wiring hole 16 is designed to facilitate the passage of wires so as to make electrical connections with external equipment of the shielding cavity 4. Moreover, the design of the wiring hole 16, through reasonable position and size, will not affect the shielding effect of the shielding cavity 4.

[0047] Specifically, the signal amplification module 33 includes a circuit board 331 and an amplification unit disposed on the circuit board 331. The amplification unit is used for signal amplification, signal splitting and balanced output. The amplification unit is electrically connected to the field-effect transistor Q131.

[0048] The circuit board 331 is a double-sided printed circuit board 331. The dimensions of the circuit board 331 are 50 mm in length, 13.6 mm in width, and 1.2 mm in thickness. The substrate of the circuit board 331 is FR4 epoxy fiberglass board. The circuit board 331 is disposed in the mounting cavity 19 of the tube body 12.

[0049] Specifically, the amplification unit includes a secondary amplification section 332, a non-inverting amplification section 333, and an inverting amplification section 334. The secondary amplification section 332 is electrically connected to the field-effect transistor Q131 and the connector 35, and is used to amplify audio signals. The non-inverting amplification section 333 is electrically connected to the secondary amplification section 332, and is used to amplify and output a non-inverting output signal to the connector. The inverting amplification section 334 is electrically connected to the secondary amplification section 332, and is used to amplify and generate an inverted output signal to the connector.

[0050] Furthermore, the secondary amplification section 332 includes a fourth transistor Q4, which is an NPN transistor.

[0051] The drain of MOSFET Q131 is electrically connected to the first terminal of the twelfth capacitor C12. The second terminal of the twelfth capacitor C12 is electrically connected to the first terminal of the fourteenth capacitor C14. The second terminal of the fourteenth capacitor C14 is electrically connected to the base (B) of the fourth transistor Q4. The second terminal of the fourteenth capacitor C14 is also electrically connected to the first terminal of the nineteenth resistor R19. The second terminal of the nineteenth resistor R19 is electrically connected to the first terminal of the first resistor R1. The second terminal of the first resistor R1 is electrically connected to the collector (C) of the fourth transistor Q4. The drain of MOSFET Q131 is electrically connected to the first terminal of the second resistor R2. The second terminal of the second resistor R2 is electrically connected to the first terminal of the fourth resistor R4. The second terminal of the fourth resistor R4 is electrically connected to the first terminal of the seventh resistor R7. The second terminal of the seventh resistor R7 is electrically connected to the first terminal of the fourteenth capacitor C14. The second terminal of the second resistor R2 is also electrically connected to the first terminal of the sixth resistor R6. The second terminal of the sixth resistor R6 is electrically connected to the base of the fourth transistor Q4. The emitter (E) of the fourth transistor Q4 is electrically connected to the first terminal of the fourth capacitor C4, and the second terminal of the fourth capacitor C4 is electrically connected to the first terminal of the ninth resistor R9.

[0052] The audio signal, after being output from the drain of the field-effect transistor Q131, is coupled to the base of the fourth transistor Q4 through the series coupling of the twelfth capacitor C12 and the fourteenth capacitor C14, achieving high-pass filtering and suppressing low-frequency noise. The audio signal is then input to the collector of the fourth transistor Q4 through the nineteenth resistor R19 and the first resistor R1, simultaneously providing a bias current path for the base of the fourth transistor Q4. The audio signal is also input to the base of the fourth transistor Q4 through the second resistor R2 and the sixth resistor R6. The second resistor R2, the fourth resistor R4, and the seventh resistor R7 are connected in series to the first terminal of the fourteenth capacitor C14, forming a negative feedback network. That is, the audio signal output from the drain of the field-effect transistor Q131 is fed back to the base of the fourth transistor Q4 through the second resistor R2 and the sixth resistor R6. If the output audio signal increases, the feedback voltage will suppress the base of the fourth transistor Q4, forming a dynamic balance, thereby stabilizing the amplification factor and reducing distortion. The audio signal input to the fourth transistor Q4 is amplified a second time. The amplified audio signal is then output from the emitter of the fourth transistor Q4 and transmitted through the fourth capacitor C4 and the ninth resistor R9.

[0053] Specifically, the inverting amplifier section 333 includes a second transistor Q2, which is an NPN transistor.

[0054] The second terminal of the ninth resistor R9 is electrically connected to the base (B) of the second transistor Q2. The second terminal of the ninth resistor R9 is electrically connected to the first terminal of the fifth resistor R5, which in turn is electrically connected to the collector (C) of the second transistor Q2. The second terminal of the fifth resistor R5 is electrically connected to the first terminal of the sixth capacitor C6, which is grounded. The emitter (E) of the second transistor Q2 is electrically connected to the first terminal of the tenth capacitor C10, which is grounded. The emitter of the second transistor Q2 is electrically connected to the first terminal of the thirteenth resistor R13. Connector 35 is an XLR connector used for signal and power transmission between audio devices. Connector 35 is fixedly connected inside the tube body 12. The second terminal of the thirteenth resistor R13 is electrically connected to the second pin (Hot / positive) of connector 35.

[0055] The audio signal is output from the ninth resistor R9 to the base of the second transistor Q2, turning on the base of Q2. Simultaneously, the audio signal flows through the fifth resistor R5 to the collector of the second transistor Q2, and a tertiary amplified audio signal is output from the emitter of Q2. The fifth resistor R5 and the grounded sixth capacitor C6 form a power supply decoupling network to suppress high-frequency noise. The tertiary amplified audio signal is input to the second pin of connector 35, and the thirteenth resistor R13 provides output impedance matching.

[0056] In addition, the inverting amplifier section 334 includes a fifth transistor Q5, which is an NPN transistor.

[0057] The second terminal of the first resistor R1 is electrically connected to the first terminal of the fifth capacitor C5. The second terminal of the fifth capacitor C5 is electrically connected to the first terminal of the tenth resistor R10. The second terminal of the tenth resistor R10 is electrically connected to the base (B) of the fifth transistor Q5. The second terminal of the tenth resistor R10 is electrically connected to the first terminal of the eighth resistor R8. The second terminal of the eighth resistor R8 is electrically connected to the collector (C) of the fifth transistor Q5. The second terminal of the fifth resistor R5 is electrically connected to the collector of the fifth transistor Q5. The emitter (E) of the fifth transistor Q5 is electrically connected to the first terminal of the eighth capacitor C8, and the second terminal of the eighth capacitor C8 is grounded. The emitter of the fifth transistor Q5 is electrically connected to the third pin (Cold / Inverting) of connector 35. The first pin (GND) of connector 35 is grounded.

[0058] The audio signal is shunted from the first resistor R1, passes sequentially through the fifth capacitor C5 and the tenth resistor R10, and is input to the base of the fifth transistor Q5. The audio signal is also shunted from the fifth resistor R5 and input to the collector of the fifth transistor Q5. The emitter of the fifth transistor Q5 is connected to the third pin of connector 35 through the eighth capacitor C8. The output of the fifth transistor Q5 is a signal with opposite phase and equal amplitude to that of the signal at the second pin, forming a differential balanced output. Through the circuit formed by the differential balanced output via the non-inverting amplifier 333 and the inverting amplifier 334, common-mode signals from external interference can be effectively suppressed, leaving only the true signal difference. Therefore, it has strong anti-interference capability and is suitable for long-distance transmission.

[0059] Specifically, the voltage regulator unit 34 includes a sixth transistor Q6 and a Zener diode Z1. The sixth transistor Q6 is an NPN transistor.

[0060] The second terminal of the fifth resistor R5 is electrically connected to the first terminal of the third resistor R3. The second terminal of the third resistor R3 is electrically connected to the base (B) of the sixth transistor Q6. The second terminal of the fifth resistor R5 is electrically connected to the collector (C) of the sixth transistor Q6. The second terminal of the third resistor R3 is electrically connected to the first terminal of the eleventh capacitor C11, and the second terminal of the eleventh capacitor C11 is grounded. The emitter (E) of the sixth transistor Q6 is electrically connected to the first terminal of the sixth resistor R6. The Zener diode Z1 is model MM3Z6V8. The second terminal of the third resistor R3 is also electrically connected to the first terminal of the Zener diode Z1. The second terminal of the Zener diode Z1 is electrically connected to the MIC- pin of the microphone MIC32.

[0061] The audio signal is output from the ninth resistor R9, and after being divided by the fifth resistor R5 and the third resistor R3, it drives the base of the sixth transistor Q6 to conduct. Simultaneously, the fifth resistor R5 provides a bias voltage to the collector of the sixth transistor Q6, and the emitter of the sixth transistor Q6 outputs the audio signal, which is then fed back to the base of the fourth transistor Q4 through the sixth resistor R6. A regulated current is input from the Zener diode Z1 to the MIC- pin of the microphone capsule MIC32, thus regulating the voltage of the entire microphone circuit 3, especially the microphone capsule MIC32 and the field-effect transistor Q131.

[0062] The implementation principle of this application is as follows:

[0063] The shielding cavity 4 inside the metal shielding cover 2 has a smaller space and more comprehensive shielding, capable of completely blocking external electromagnetic interference to the microphone MIC32 and the field-effect transistor Q131. By using the metal shielding cover 2, even if the microphone head 11 and tube body 12 are not made of metal, thus saving on the cost of the microphone housing 1, interference resistance and prevention of current noise can still be achieved. At the same time, the elimination of the need for an all-metal microphone housing 1 helps reduce the overall weight of the microphone, improving ease of use and comfort, especially during extended use, reducing hand fatigue and enhancing the user experience.

[0064] The microphone circuit 3 converts the weak microphone signal into a balanced audio signal with a high signal-to-noise ratio and anti-interference capability, which is suitable for professional recording environments and further reduces the generation of current noise.

[0065] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this utility model, and these modifications or substitutions should all be covered within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A corded microphone for cancelling current sound, comprising a microphone housing (1), characterized in that: The microphone housing (1) is provided with a metal shield (2) and a microphone circuit (3). The metal shield (2) is detachably connected to the microphone housing (1). The metal shield (2) forms a shielding cavity (4) that shields external electromagnetic interference in all directions. The microphone circuit (3) includes a field-effect transistor Q1 (31), which is located in the shielding cavity (4).

2. A wired microphone that eliminates current sound according to claim 1, characterized in that: The metal shield (2) includes a shield base (21) with one end open and a shield cover (22) detachably connected to the shield base (21); the shield cover (22) has a sound pickup hole (5) and a metal mesh (6) covering the sound pickup hole (5) is provided on the shield cover (22).

3. A wired microphone that eliminates current sound according to claim 1, characterized in that: The microphone housing (1) includes a cup head (11) and a tube body (12) detachably connected to the cup head (11). The side wall of the cup head (11) and the end away from the tube body (12) are provided with sound holes (7). The inner wall of the cup head (11) is provided with an internal thread (8). The end of the tube body (12) near the cup head (11) is provided with an external thread (9). The internal thread (8) and the external thread (9) cooperate with each other.

4. A wired microphone that eliminates current sound according to claim 2, characterized in that: The outer wall of the shielding base (21) is provided with an external thread (10), and the shielding cover (22) is provided with an internal thread (13) that is compatible with the shielding base (21).

5. A wired microphone that eliminates current sound according to claim 2, characterized in that: The shielding base (21) is provided with an external thread three (14), and the inner side of the tube body (12) is provided with an internal thread three (15). The internal thread three (15) and the external thread three (14) cooperate with each other. When the metal shielding cover (2) is connected to the tube body (12), the end of the metal shielding cover (2) near the shielding cover (22) is located inside the cup head (11).

6. A wired microphone that eliminates current sound according to claim 2, characterized in that: The shielding base (21) has a line hole (16) at one end away from the shielding cover (22), through which the power supply line passes.

7. A wired microphone that eliminates current sound according to claim 1, characterized in that: The microphone circuit (3) also includes: The microphone (32) is used to convert sound waves into audio signals. The microphone (32) is electrically connected to the field-effect transistor Q1 (31). Signal amplification module (33), which is electrically connected to field-effect transistor Q1 (31), is used to amplify audio signals; A voltage regulator unit (34) is electrically connected to the microphone (32) and the signal amplification module (33). The voltage regulator unit (34) is used to regulate the voltage of the microphone (32) and the field effect transistor Q1 (31). Connector (35), which is electrically connected to signal amplification module (33), is used to output audio signals.

8. A wired microphone that eliminates current sound according to claim 7, characterized in that: The microphone (32) is located in the shielding cavity (4), and the shielding base (21) is provided with a support (17). The support (17) is just right for the microphone (32) to be placed and for the microphone (32) to be close to the metal mesh (6).

9. A corded microphone that eliminates current sound according to claim 7, characterized in that: The signal amplification module (33) includes a circuit board (331) and an amplification unit disposed on the circuit board (331). The amplification unit is used for signal amplification, signal splitting and balanced output. The amplification unit is electrically connected to the field effect transistor Q1 (31) and the connector (35).

10. A wired microphone that eliminates current sound according to claim 9, characterized in that: The amplification unit includes a secondary amplification section (332), a non-inverting amplification section (333), and an inverting amplification section (334). The secondary amplification section (332) is electrically connected to the field-effect transistor Q1 (31) and is used to amplify audio signals. The non-inverting amplification section (333) is electrically connected to the secondary amplification section (332) and is used to amplify and output a non-inverting output signal to the connector (35). The inverting amplification section (334) is electrically connected to the secondary amplification section (332) and is used to amplify and generate an inverting output signal to the connector (35).

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