Noise reducer for family telephone conversation in prison

Abstract

The utility model discloses a prison family telephone conversation denoiser, which comprises a telephone receiver connected with a fixed telephone host and a noise reduction assembly arranged on the telephone receiver, and the noise reduction assembly comprises a cover body covered on the telephone receiver; the flexible circuit board is mounted on the inner wall of the cover body, and the flexible circuit board comprises a power interface and a noise reduction control circuit; the microphone array is arranged at the position, opposite to the front end and the rear end of the receiver, of the cover body; the sound-absorbing material layer is mounted on the inner wall of the cover body and opposite to the front end of the receiver, and a sound-insulating cavity is formed in the position, close to the receiver, of the sound-absorbing material layer; the noise reduction loudspeaker is installed in the sound insulation cavity. According to the utility model, firstly, the feedforward microphone and the feedback microphone are combined, so that the recognition precision and the response speed of noise in different directions and frequencies are improved; and secondly, the noise reduction loudspeaker is arranged in the sound insulation cavity, so that direct contact with the receiver loudspeaker is avoided, and the problem of sound interference or resonance is reduced.

Description

Technical Field

[0001] This utility model relates to the field of fixed-line telephone technology, and in particular to a noise reduction device for family phone calls in prisons. Background Technology

[0002] In the field of landline telephone technology, especially in environments requiring high privacy and security, such as prison family calls, the application of noise reduction technology is particularly important. Currently, a Chinese utility model patent with publication number CN210053456U discloses "a noise reduction accessory with active noise reduction function, comprising: a housing for being fitted over the outside of the earpiece; a circuit board including an electrically connected power interface and a noise reduction control circuit; a microphone fixed outside the housing and electrically connected to the input terminal of the noise reduction control circuit for receiving ambient noise; and a noise-canceling speaker fixed to the side of the housing near the ear and electrically connected to the output terminal of the noise reduction control circuit for emitting sound with a phase opposite to the noise."

[0003] However, this existing technology has shortcomings in use. First, it adopts a single feedforward structure and relies on only one external microphone to collect noise information, which makes its noise reduction effect easily affected by the direction and distance of the noise source, making it difficult to achieve effective noise reduction in all directions. Second, the design of directly attaching the noise-canceling speaker to the outside of the earpiece speaker can easily cause sound interference or resonance problems, thereby affecting call quality. Utility Model Content

[0004] The purpose of this utility model is to provide a noise reduction device for prison family phone calls in order to solve the technical problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A noise reduction device for prison family phone calls includes a handset connected to a landline main unit, and a noise reduction component installed on the handset. The noise reduction component includes:

[0007] The cover is placed over the earpiece;

[0008] A flexible circuit board is installed on the inner wall of the enclosure. The flexible circuit board includes a power interface and a noise reduction control circuit.

[0009] A microphone array is positioned on the housing opposite the front and rear ends of the earpiece, and the microphone array is electrically connected to the input terminal of the noise reduction control circuit.

[0010] A sound-absorbing material layer is installed on the inner wall of the cover at a position opposite to the front end of the earpiece. The sound-absorbing material layer has a sound insulation cavity near the earpiece, as well as several sound outlet holes communicating with the sound insulation cavity.

[0011] A noise-canceling speaker is installed inside a soundproof cavity, and the noise-canceling speaker is connected to the output terminal of a noise-canceling control circuit.

[0012] The 1-to-2 adapter cable electrically connects the handset, the flexible circuit board, and the landline main unit.

[0013] As a further description of the above technical solution:

[0014] The microphone array includes:

[0015] A feedforward microphone is mounted on the outside of the housing, opposite the rear end of the earpiece;

[0016] The feedback microphone is installed inside the housing, opposite the front of the earpiece.

[0017] Both the feedforward microphone and the feedback microphone are electrically connected to the input terminal of the noise reduction control circuit via FPC flexible flat cables.

[0018] As a further description of the above technical solution:

[0019] The feedforward microphone is configured in two units.

[0020] As a further description of the above technical solution:

[0021] The sound-absorbing material layer is made of one of the following materials: EVA foam, sponge, or porous sound-absorbing material.

[0022] As a further description of the above technical solution:

[0023] The one-to-two adapter cable includes:

[0024] The first RJ12 terminal is electrically connected to the handset interface of the landline host.

[0025] The second RJ12 terminal is electrically connected to the handset.

[0026] The power terminal is electrically connected to the power interface of the flexible circuit board.

[0027] As a further description of the above technical solution:

[0028] The cover is a hollow cup-shaped structure made of silicone or TPU soft material, mimicking the shape of a earpiece.

[0029] As a further description of the above technical solution:

[0030] The cover is open at the bottom and closed at the top, and the inner wall of the cover is provided with a slot to accommodate a flexible circuit board.

[0031] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0032] 1. In this utility model, the combination of feedforward and feedback microphones improves the recognition accuracy and response speed of noise from different directions and frequencies.

[0033] 2. In this utility model, the noise-reducing speaker is placed inside the soundproof cavity to avoid direct contact with the earpiece speaker, thereby reducing sound interference or resonance problems.

[0034] 3. In this utility model, the sound-absorbing material layer can effectively absorb high-frequency reflected sound and structural vibration noise, thereby enhancing the overall quietness effect. Attached Figure Description

[0035] Figure 1 A schematic diagram of the structure of a prison family phone call noise reduction device according to an embodiment of the present invention is shown;

[0036] Figure 2 The present invention provides an embodiment of the present invention. Figure 1 Enlarged view of point A in the middle;

[0037] Figure 3 A schematic diagram illustrating the control principle of a prison family phone call noise reduction device according to an embodiment of the present invention is shown.

[0038] Legend:

[0039] 1. Earpiece; 2. Split-to-2 adapter cable; 3. Noise reduction component; 31. Enclosure; 32. Feedforward microphone; 33. Feedback microphone; 34. Flexible circuit board; 35. Sound-absorbing material layer; 3501. Sound insulation cavity; 3502. Sound outlet; 36. Noise-canceling speaker. Detailed Implementation

[0040] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0041] Please see Figure 1-3This utility model provides a technical solution: a noise reduction device for prison family phone calls, including a handset 1 connected to a landline host, and a noise reduction component 3 installed on the handset 1. The noise reduction component 3 includes: a cover 31 covering the handset 1, the cover 31 being a hollow cup-shaped structure made of silicone or TPU soft material, with an open bottom and a closed top, mimicking the shape of the handset 1, having good fit and sealing, forming a relatively closed acoustic space, providing a basis for subsequent noise reduction processing; two feedforward microphones 32 installed on the outside of the cover 31 opposite to the rear end of the handset 1, used to collect background noise signals from the external environment in real time; a feedback microphone 33 installed on the inside of the cover 31 opposite to the front end of the handset 1, used to collect sound signals that remain inside the handset 1 after noise reduction processing, including noise that has not been completely canceled and interference components that may be mixed into the speech; the two microphone signals are transmitted to a flexible electrical circuit via an FPC flexible flat cable. The noise reduction control circuit on the circuit board 34 performs analysis and processing; the inner wall of the cover 31 is provided with a slot for accommodating the flexible circuit board 34. The flexible circuit board 34 includes a power interface and a noise reduction control circuit. The noise reduction control circuit generates an anti-phase sound wave signal with the opposite phase to the current noise by using a digital filtering algorithm (such as LMS adaptive filtering) based on the noise signal collected by the feedforward and feedback microphones. The signal is then driven by the noise reduction speaker 36 through the output terminal. It should be noted that the noise reduction control circuit is existing technology and will not be described in detail in this embodiment. The sound-absorbing material layer 35 is installed on the inner wall of the cover 31 at a position opposite to the front end of the earpiece 1. The sound-absorbing material layer 35 is provided with a sound insulation cavity 3501 for accommodating the noise reduction speaker 36 near the earpiece 1, as well as several sound outlet holes 3502 communicating with the sound insulation cavity 3501. The noise reduction speaker 36 releases the anti-phase sound wave evenly to the space around the earpiece through multiple sound outlet holes 3502, and achieves effective noise cancellation after being superimposed with the original noise.

[0042] In this embodiment, firstly, by combining feedforward and feedback microphones, the recognition accuracy and response speed of noise from different directions and frequencies are improved; secondly, the noise-canceling speaker 36 is placed inside the soundproof cavity 3501 to avoid direct contact with the speaker of the earpiece 1, thereby reducing sound interference or resonance problems.

[0043] Specifically, such as Figure 2 and Figure 3 As shown, the first RJ12 terminal of the 1-to-2 adapter cable 2 is electrically connected to the handset interface of the landline host, and the second RJ12 terminal of the 1-to-2 adapter cable 2 is electrically connected to the handset 1, ensuring normal transmission of the call signal; the power terminal of the 1-to-2 adapter cable 2 is electrically connected to the power interface of the flexible circuit board 34, providing a stable power supply to the flexible circuit board 34 and ensuring continuous operation of the noise reduction module. The 1-to-2 adapter cable 2 enables plug-and-play functionality, adapting to various models of landline telephone equipment, and is suitable for secure communication needs in special scenarios such as prisons.

[0044] Specifically, such as Figure 2 As shown, the sound-absorbing material layer 35 is made of one of the following materials: EVA foam, sponge, or porous sound-absorbing material, which effectively absorbs high-frequency reflected sound and structural vibration noise, and enhances the overall quietness effect.

[0045] Working principle: When in use, when the user picks up the handset 1 to start a call, the feedforward microphone 32 starts working, monitoring and collecting noise signals in the external environment of the handset 1 in real time, including continuous low-frequency humming and intermittent high-frequency noise. At the same time, the feedback microphone 33 listens to the audio signal after preliminary noise reduction processing, detecting whether there is residual noise or new noise entering the call path. Then, the noise reduction control circuit on the flexible circuit board 34 receives the noise signals from the feedforward and feedback microphones, and analyzes and processes these signals through built-in algorithms (such as the LMS adaptive filtering algorithm). Based on the noise characteristics, the noise reduction control circuit calculates the corresponding inversion. The sound wave signal, which has the same amplitude but opposite phase as the original noise, is calculated and sent to the noise-canceling speaker 36. The anti-phase sound wave emitted by the noise-canceling speaker 36 propagates out through the sound outlet 3502 and meets the noise from the outside. They cancel each other out in the physical space, thereby significantly reducing the noise level reaching the user's ears. Throughout the process, the sound-absorbing material layer 35 further absorbs the remaining high-frequency reflected sound and structural vibration noise, ensuring that the call environment is as quiet as possible, so that the user can hear the other party's voice more clearly, and the other party can also better understand what they are saying, greatly improving the quality and efficiency of the call.

[0046] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A noise reduction device for prison family phone calls, comprising a handset (1) connected to a landline main unit, and a noise reduction assembly (3) disposed on the handset (1), characterized in that, The noise reduction component (3) includes: The cover (31) is placed over the earpiece (1); A flexible circuit board (34) is installed on the inner wall of the cover (31), and the flexible circuit board (34) includes a power interface and a noise reduction control circuit. A microphone array is arranged on the cover (31) at a position opposite to the front and rear ends of the earpiece (1), and the microphone array is electrically connected to the input terminal of the noise reduction control circuit; The sound-absorbing material layer (35) is installed on the inner wall of the cover (31) at a position opposite to the front end of the earpiece (1). The sound-absorbing material layer (35) is provided with a sound insulation cavity (3501) near the earpiece (1) and a number of sound outlet holes (3502) communicating with the sound insulation cavity (3501). A noise-reducing speaker (36) is installed inside a soundproof cavity (3501), and the noise-reducing speaker (36) is connected to the output terminal of a noise reduction control circuit; The one-to-two adapter cable (2) is electrically connected between the handset (1), the flexible circuit board (34), and the landline host.

2. The prison family phone call noise reduction device according to claim 1, characterized in that, The microphone array includes: A feedforward microphone (32) is installed on the outside of the housing (31) opposite to the rear end of the earpiece (1); Feedback microphone (33) is installed inside the cover (31) at a position opposite to the front end of the earpiece (1); Both the feedforward microphone (32) and the feedback microphone (33) are electrically connected to the input terminal of the noise reduction control circuit via FPC flexible flat cables.

3. The prison family phone call noise reduction device according to claim 2, characterized in that, The number of feedforward microphones (32) is set to two.

4. The prison family phone call noise reduction device according to claim 1, characterized in that, The sound-absorbing material layer (35) is made of one of the following materials: EVA foam, sponge, or porous sound-absorbing material.

5. The prison family phone call noise reduction device according to claim 1, characterized in that, The one-to-two adapter cable (2) includes: The first RJ12 terminal is electrically connected to the handset interface of the landline host. The second RJ12 terminal is electrically connected to the earpiece (1); The power supply terminal is electrically connected to the power interface of the flexible circuit board (34).

6. The prison family phone call noise reduction device according to claim 1, characterized in that, The cover (31) is a hollow cup-shaped structure made of silicone or TPU soft material, mimicking the shape of a earpiece (1).

7. The prison family phone call noise reduction device according to claim 6, characterized in that, The cover (31) is open at the bottom and closed at the top, and the inner wall of the cover (31) is provided with a slot for accommodating a flexible circuit board (34).

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