Audio isolation device of surveillance camera, audio isolation circuit of surveillance camera and use method of audio isolation device

Abstract

The invention discloses an audio isolation device of a surveillance camera, an audio isolation circuit of the surveillance camera and a use method of the audio isolation device, and the audio isolation device comprises an audio input part, the audio isolation circuit and an audio output part, a primary coil and a secondary coil of each isolation transformer are respectively connected with an input interface of the audio input part and an output interface of the audio output part through signal lines. The isolation transformer of the audio isolation circuit can isolate an audio input signal from an audio output signal, thereby avoiding signal interference and loss.

Description

Technical Field

[0001] The present invention relates to the technical field of monitoring and tracking, and in particular to an audio isolation device of a monitoring camera and an audio isolation circuit and a use method thereof. Background Art

[0002] A camera is a device used to record images. It is widely used in various scenarios in the fields of film, TV program production, home monitoring, security monitoring, etc. Among them, security monitoring cameras are required not only to record historical images, but also to record the on-site sounds at the time. At present, there are two main methods for collecting sound signals in the security industry. One is to use the camera's own pickup device. The general camera's own pickup effect is poor and cannot meet the security industry's high-definition voice requirements; the second is to connect an independent pickup device. According to the way it collects sound, security pickups can be divided into omnidirectional and directional types.

[0003] Currently, the common methods of connecting external pickup devices between cameras and microphones include three-wire system and RCA direct connection. Although both methods can directly connect the audio output signal of the microphone to the audio input signal of the camera, the existing pickup equipment only has the function of picking up sound. The installation environment of general security industry surveillance cameras is relatively complex and the on-site electromagnetic interference is relatively serious. It cannot reduce external interference, let alone eliminate the noise caused by electromagnetic interference in complex environments, thereby reducing the sound quality. Summary of the invention

[0004] In view of the above problems, the purpose of the present invention is to provide an audio isolation device for a surveillance camera, an audio isolation circuit and a method of use thereof, so as to solve the problem that the existing wiring method has poor anti-interference ability and cannot eliminate electromagnetic interference and noise in complex on-site environments, thereby reducing sound quality.

[0005] To achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention discloses an audio isolation device for a surveillance camera, comprising: The audio input section includes 1 to 3 audio input interfaces for connecting to the microphone of an external surveillance camera; The audio output section includes 1 to 3 audio output interfaces for connecting to external audio output devices; An audio isolation circuit, comprising 1 to 2 isolation transformers, wherein the primary coil and the secondary coil of each isolation transformer are respectively connected to the input interface of the audio input part and the output interface of the audio output part through signal lines, respectively forming a mono mode, a left and right dual-channel mode, a mixed stereo channel mode, and a mode of a combination of left and right dual-channel and mixed stereo channels; Among them, in any one of the mono mode, left and right dual channel mode, mixed stereo channel mode and the combination of left and right dual channel and mixed stereo channel mode, in the process of converting the audio output signal and the audio input signal through the isolation transformer, the isolation transformer of the audio isolation circuit can isolate the audio input signal from the audio output signal to avoid signal interference and loss.

[0006] Specifically, the isolation transformer includes an iron core, and the windings of the primary coil and the secondary coil on the iron core are the same.

[0007] Specifically, the audio input interface of the audio input unit receives an audio input signal, and the audio output interface of the audio output unit outputs an audio output signal. When the audio input signal and the audio output signal are converted through the audio isolation circuit, the high-frequency loss characteristics of the iron core of the isolation transformer can avoid interference of external signals on the audio signal, and the isolated electrical connection between the primary coil and the secondary coil can filter the electrical impact of the external environment on the audio signal, further prevent external interference, and ultimately achieve isolation of the audio signal from external noise.

[0008] As a preferred embodiment, the audio input part includes an input socket, the input socket includes a central ferrule hole, and a grounding ring is arranged on the outer periphery of the central ferrule hole; The audio output part includes an output socket, the output socket includes a central ferrule hole, and a grounding ring is arranged on the outer periphery of the central ferrule hole; The audio isolation circuit includes an isolation transformer, the isolation transformer includes an iron core, and the two sides of the iron core are respectively wound with a primary coil and a secondary coil; The input end of the primary coil is connected to the central ferrule hole of the input socket of the audio input part, and the output end of the primary coil is connected to the grounding ring of the input socket of the audio input part; The input end of the secondary coil is connected to the central ferrule hole of the output socket of the audio output part, and the output end of the secondary coil is connected to the grounding ring of the output socket of the audio output part.

[0009] As a preferred embodiment, the audio input part comprises a left input socket and a right input socket, and the left input socket and the right input socket both comprise a central ferrule hole and a grounding ring outside thereof; The audio output part comprises a left output socket and a right output socket, and the left output socket and the right output socket each comprise a central ferrule hole and a grounding ring outside thereof; The audio isolation circuit includes a left isolation transformer and a right isolation transformer, The left isolation transformer comprises a left iron core, and a left primary coil and a left secondary coil are respectively wound on both sides of the left iron core, and the input end and the output end of the left primary coil are respectively connected to the central core insertion hole and the grounding ring of the left input socket; the input end and the output end of the left secondary coil are respectively connected to the central core insertion hole and the grounding ring of the left output socket; The right isolation transformer includes a right iron core, and a right primary coil and a right secondary coil are respectively wound on both sides of the right iron core. The input end and the output end of the right primary coil are respectively connected to the central core hole and the outer ring of the right input socket; the input end and the output end of the right secondary coil are respectively connected to the central core hole and the grounding ring of the right output socket.

[0010] Furthermore, the output end of the left primary coil is connected to the output end of the right primary coil; the output end of the left secondary coil is connected to the output end of the right secondary coil.

[0011] As a preferred embodiment, the audio input part comprises a stereo input socket, and the stereo input socket comprises a central ferrule hole and a grounding ring outside thereof; The audio output part comprises a stereo output socket, and the stereo output socket comprises a central ferrule hole and a grounding ring outside thereof; The audio isolation circuit includes a left isolation transformer and a right isolation transformer, and the stereo input socket is connected to the stereo output socket through the left isolation transformer and the right isolation transformer respectively.

[0012] Further, the left isolation transformer comprises a left iron core, and a left primary coil and a left secondary coil are respectively wound on both sides of the left iron core, and the input end and the output end of the left primary coil are respectively connected to the central ferrule hole and the grounding ring of the stereo input socket; the input end and the output end of the left secondary coil are respectively connected to the central ferrule hole and the grounding ring of the stereo input socket; The right isolation transformer comprises a right iron core, and a right primary coil and a right secondary coil are respectively wound on both sides of the right iron core, and the input end and the output end of the right primary coil are respectively connected to the central core hole and the outer ring of the stereo output socket; the input end and the output end of the right secondary coil are respectively connected to the central core hole and the grounding ring of the stereo output socket.

[0013] Furthermore, the audio input unit further comprises a left input socket and a right input socket, and the left input socket and the right input socket both comprise a central ferrule hole and a grounding ring outside thereof; The audio output unit further comprises a left output socket and a right output socket, wherein the left output socket and the right output socket both comprise a central ferrule hole and a grounding ring outside thereof; The input end and output end of the left primary coil of the left isolation transformer are respectively connected to the central ferrule hole and the grounding ring of the left input socket, and the input end and output end of the left secondary coil are respectively connected to the central ferrule hole and the grounding ring of the left output socket; The input end and output end of the right primary coil of the right isolation transformer are respectively connected to the central core hole and outer ring of the right input socket, and the input end and output end of the right secondary coil are respectively connected to the central core hole and grounding ring of the right output socket.

[0014] In a second aspect, the present invention further discloses an audio isolation circuit in the above-mentioned audio isolation device, comprising a left isolation transformer and a right isolation transformer, The left isolation transformer comprises a left iron core, and a left primary coil and a left secondary coil are respectively wound on both sides of the left iron core; the right isolation transformer comprises a right iron core, and a right primary coil and a right secondary coil are respectively wound on both sides of the right iron core; The output end of the left primary coil is connected to the output end of the right primary coil, and the output end of the left secondary coil is connected to the output end of the right secondary coil, forming the audio isolation circuit.

[0015] In a third aspect, the present invention further discloses a method for using an audio isolation device, wherein the above-mentioned audio isolation device is used, and the audio input portion of the audio isolation device is externally connected to a microphone of a surveillance camera, and the method for using the audio isolation device comprises: The pickup converts the sound signal into an electrical signal, and the electrical signal passes through the audio input part as an audio input signal; The stereo input socket receives audio input signals individually or simultaneously with the left and right input sockets; The audio input signal is simultaneously transmitted to the primary coil of the left isolation transformer and / or the right isolation transformer, and the iron core of the left isolation transformer and / or the right isolation transformer simultaneously generates the left alternating magnetic flux and / or the right alternating magnetic flux respectively; The left alternating magnetic flux passes through the primary coil and the secondary coil of the left isolation transformer, and generates induced electromotive force in both the primary coil and the secondary coil of the left isolation transformer, and / or the right alternating magnetic flux passes through the primary coil and the secondary coil of the right isolation transformer, and generates induced electromotive force in both the primary coil and the secondary coil of the right isolation transformer; The iron core of the left isolation transformer converts the voltage and current on the primary coil side into the voltage and current on the secondary coil side through electromagnetic induction, and / or the iron core of the right isolation transformer converts the voltage and current on the primary coil side into the voltage and current on the secondary coil side through electromagnetic induction; The voltage and current on the secondary coil side of the left isolation transformer and / or the right isolation transformer are outputted through the stereo output socket in the audio output part alone or through the left output socket and the right output socket simultaneously to form an audio output signal; Among them, in the process of converting the audio output signal and the audio input signal through the isolation transformer, not only can the high-frequency loss characteristics of the iron core of the isolation transformer avoid the interference of external signals on the audio signal, but also because the primary coil and the secondary coil are isolated and electrically connected, the electrical impact of the external environment on the audio signal can be filtered, further preventing external interference, and finally achieving the isolation of the audio signal from external noise.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (I) The present invention discloses an audio isolation device for a surveillance camera, comprising an audio input unit, an audio isolation circuit and an audio output unit, wherein the audio isolation circuit comprises at least one isolation transformer, the primary coil and the secondary coil of each isolation transformer are respectively connected to the input interface of the audio input unit and the output interface of the audio output unit through a signal line, and in the process of converting the audio output signal and the audio input signal through the isolation transformer, the isolation transformer of the audio isolation circuit can isolate the audio input signal from the audio output signal to avoid signal interference and loss.

[0017] (II) The present invention discloses an audio isolation device for a surveillance camera. The isolation transformer of the audio isolation circuit can isolate the potential difference between the microphone and the audio output device to prevent the device from being damaged by an excessively high potential difference, and can achieve safe transmission of audio signals, remove noise generated by the microphone connection circuit, and solve the current noise caused by power supply current, on-site electromagnetic interference, etc. The audio isolation device disclosed by the present invention has a simple structure, has no effect on the stability and safety of the original system, and has no significant sound quality loss on the output signal of the microphone itself.

[0018] (III) The present invention discloses an audio isolation device for a surveillance camera, which can effectively isolate the power supply between the microphone and the camera, and avoid noise caused by current and electromagnetic interference, which affects the sound pickup effect. The present invention discloses an audio isolation device for a surveillance camera, which can be applied to the audio isolation device between the microphone and the camera, and solves the current sound caused by power supply current, on-site electromagnetic interference and other reasons.

[0019] (IV) The present invention discloses an audio isolation device for a surveillance camera, which reduces external interference, eliminates electromagnetic interference and noise in complex on-site environments, improves sound quality, and solves the problem of audio interference. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a circuit diagram of a monophonic audio isolation device provided in Embodiment 2 of the present invention; Figure 2 is a circuit diagram of an audio isolation device when the left and right channels are separated in a left and right dual-channel mode provided by Embodiment 3 of the present invention; Figure 3 is a circuit diagram of an audio isolation device when left and right channels are integrated in a left and right dual-channel mode provided by Embodiment 3 of the present invention; Figure 4 is a circuit diagram of an audio isolation device in a mixed stereo channel mode provided by Embodiment 4 of the present invention; Figure 5 It is a circuit diagram of an audio isolation device having a comprehensive mode of both left and right dual channels and mixed stereo channels provided by Embodiment 5 of the present invention; Figure 6 It is a structural schematic diagram of the audio isolation circuit provided in Example 6 of the present invention.

[0021] Description of reference numerals: 1- audio input part, 10- stereo input socket, 11- left input socket, 12- right input socket; 2-audio isolation circuit, 21-left isolation transformer, 22-right isolation transformer; 3- audio output part, 30- stereo output socket, 31- left output socket, 32- right output socket; L1-primary coil, L2-secondary coil; I1-input end of the left primary coil, O1-output end of the left primary coil; I'1-input end of the left secondary coil, O'1-output end of the left secondary coil; I2-input terminal I2 of the right primary coil, O2-output terminal of the right primary coil; I'2-input end of the right secondary coil, O'2-output end of the right secondary coil.

[0022] The solid arrow → in the accompanying drawings indicates the direction of the current, and the hollow dashed arrow indicates the direction of the magnetic flux lines of the alternating magnetic flux. DETAILED DESCRIPTION

[0023] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0024] In order to solve the problem that the existing wiring method has poor anti-interference ability and cannot eliminate electromagnetic interference and noise in complex on-site environments, thereby reducing sound quality, the present invention discloses an audio isolation device for a surveillance camera, comprising an audio input part 1, an audio isolation circuit 2 and an audio output part 3, wherein the audio isolation circuit 2 comprises 1 to 2 isolation transformers, and the primary coil and the secondary coil of each isolation transformer are respectively connected to the input interface of the audio input part 1 and the output interface of the audio output part 3 through a signal line, respectively forming a mono mode, a left and right dual-channel mode, a mixed stereo channel mode and a mode of combining left and right dual-channel and mixed stereo channels; in any one of the mono mode, the left and right dual-channel mode, the mixed stereo channel mode and the mode of combining left and right dual-channel and mixed stereo channels, in the process of converting the audio output signal and the audio input signal through the isolation transformer, the isolation transformer of the audio isolation circuit 2 can isolate the audio input signal from the audio output signal to avoid signal interference and loss.

[0025] Embodiment 1: An audio isolation device for a surveillance camera Embodiment 1 of the present invention provides an audio isolation device for a surveillance camera, and its structure and circuit configuration are described in detail below in conjunction with the accompanying drawings.

[0026] The audio isolation device of the surveillance camera comprises an audio input part 1, an audio isolation circuit 2 and an audio output part 3. The audio input unit 1 includes 1 to 3 audio input interfaces for connecting to the microphone of an external monitoring camera.

[0027] The audio output unit 3 includes 1 to 3 audio output interfaces for connecting to external audio output devices.

[0028] The audio isolation circuit 2 includes 1 to 2 isolation transformers, and the primary coil and the secondary coil of each isolation transformer are respectively connected to the input interface of the audio input part 1 and the output interface of the audio output part 3 through signal lines, forming a mono mode, a left and right dual channel mode, a mixed stereo channel mode, and a combination of left and right dual channel and mixed stereo channel mode.

[0029] Among them, in any mode among the mono mode, left and right dual channel mode, mixed stereo channel mode and the combination of left and right dual channel and mixed stereo channel mode, in the process of the audio output signal and the audio input signal being transformed through the isolation transformer, the isolation transformer of the audio isolation circuit 2 can isolate the audio input signal from the audio output signal to avoid signal interference and loss.

[0030] Specifically, the audio output interface of the microphone is a plug, the audio input interface of the audio input part 1 is a socket, and the audio output plug of the microphone and the socket of the audio input part 1 are coaxial audio interfaces.

[0031] Specifically, the audio output device includes a speaker, the audio input interface connected to the speaker is a plug, the audio output interface of the audio output unit 3 is a socket, and the audio input plug of the audio output device and the socket of the audio output unit 3 are coaxial audio interfaces.

[0032] In order to improve applicability, preferably, the audio input interface of the audio input part 1 and the audio output interface of the audio output part 3 use standard connectors, for example, both are coaxial audio interfaces with an inner diameter of 3.5 mm.

[0033] Among them, the microphone is a very important audio device, which is mainly used to collect sound signals and convert them into electrical signals for subsequent processing, transmission or storage.

[0034] As an isolation transformer, the isolation transformer includes an iron core, and the windings of the primary coil and the secondary coil on the iron core are the same.

[0035] Specifically, the isolation transformer adopts a 10K:10K Permalloy transformer.

[0036] When the audio input part 1 transmits an audio signal to the audio output part 3 through the audio isolation circuit 2, the audio isolation circuit 2 isolates the audio signal from external noise. The principle is as follows: When an audio input signal is input through the audio input unit 1, the audio input signal is transmitted to the primary coil of the isolation transformer, and the iron core of the isolation transformer generates an alternating magnetic flux; The alternating magnetic flux passes through the primary coil and the secondary coil at the same time, generating induced electromotive force in both the primary coil and the secondary coil, among which the primary coil side is the self-inductance electromotive force and the secondary coil side is the mutual inductance electromotive force; The iron core of the isolation transformer converts the voltage and current on the primary coil side into the voltage and current on the secondary coil side through electromagnetic induction. The voltage and current on the secondary coil side are output through the audio output unit 3 to form an audio output signal.

[0037] Among them, in the process of converting the audio output signal and the audio input signal through the isolation transformer, firstly, the high-frequency loss characteristics of the iron core of the isolation transformer can prevent the interference of external signals on the audio signal; secondly, since the primary coil and the secondary coil are completely disconnected, that is, the electrical connection is isolated, the electrical impact of the external environment on the audio signal can be filtered, further preventing external interference, and finally achieving the isolation of the audio signal from external noise.

[0038] Example 2: Mono Mode On the basis of Example 1, Example 2 provides an audio isolation device for realizing a mono mode, and its circuit structure is described in detail below in conjunction with the accompanying drawings.

[0039] refer to Figure 1 The audio input part 1 of the audio isolation device includes an input socket, which is an RCA interface, including a central ferrule hole, and a grounding ring is arranged on the periphery of the central ferrule hole; The audio output unit 3 includes an output socket, which is an RCA interface, including a central ferrule hole, and a grounding ring is arranged on the periphery of the central ferrule hole; The audio isolation circuit 2 includes an isolation transformer, which includes an iron core, with a primary coil L1 and a secondary coil L2 wound on both sides of the iron core, respectively. The windings of the primary coil L1 and the secondary coil L2 on the iron core are the same. Figure 1 shown.

[0040] Among them, the RCA interface is also called the lotus socket or AV terminal. It adopts a coaxial signal transmission method. The central axis is used to transmit the signal, and the outer circle of contact rings or shielding film is used for grounding. It is mainly used to transmit audio and video signals and supports the transmission of analog and digital signals. It is an existing technology and will not be repeated here.

[0041] The input end of the primary coil L1 is connected to the central ferrule hole of the input socket of the audio input part 1, and the output end of the primary coil L1 is connected to the grounding ring of the input socket of the audio input part 1; The input end of the secondary coil L2 is connected to the central ferrule hole of the output socket of the audio output part 3 , and the output end of the secondary coil L2 is connected to the grounding ring of the output socket of the audio output part 3 .

[0042] Among them, the audio is input from the input socket of the audio input part 1, passes through the isolation transformer of the audio isolation circuit 2, and is finally output from the output socket of the audio output part 3, forming a single channel transmission path for audio signal input and output, that is, mono mode.

[0043] In order to dock the microphone, the audio output plug of the microphone includes a central terminal and a grounding ring, and the central terminal is located at the center of the grounding ring. When the audio output plug of the microphone is inserted into the input socket of the audio input part 1, the central terminal of the audio output plug of the microphone is just inserted into the central plug hole of the input socket of the audio input part 1, and the grounding ring of the audio output plug of the microphone contacts the grounding ring of the input socket of the audio input part 1, thus achieving the docking of the audio input part 1 with the microphone of the external surveillance camera.

[0044] In order to dock with the audio output device, the audio input plug of the audio output device includes a central terminal and a grounding ring, and the central terminal is located at the center of the grounding ring. When the audio input plug of the audio output device is inserted into the output socket of the audio output part 3, the central terminal of the audio input plug of the audio output device is just inserted into the central plug hole of the output socket of the audio output part 3, and the grounding ring of the audio input plug of the audio output device is in contact with the grounding ring of the output socket of the audio output part 3, so that the audio output part 3 is docked with the external audio output device.

[0045] Example 3: Left and right dual channel mode On the basis of Example 1, Example 3 provides an audio isolation device for realizing a left and right dual channel mode, and its circuit structure is described in detail below in conjunction with the accompanying drawings.

[0046] refer to Figure 2 The audio input part 1 of the audio isolation device includes a left input socket 11 and a right input socket 12, and both the left input socket 11 and the right input socket 12 are RCA interfaces, including a central ferrule hole and a grounding ring outside thereof; The audio output part 3 includes a left output socket 31 and a right output socket 32. Both the left output socket 31 and the right output socket 32 ​​are RCA interfaces, including a central ferrule hole and a grounding ring outside thereof; The audio isolation circuit 2 includes a left isolation transformer 21 and a right isolation transformer 22. The left isolation transformer 21 includes a left iron core, and a left primary coil and a left secondary coil are respectively wound on both sides of the left iron core. The input end and the output end of the left primary coil are respectively connected to the central core hole and the grounding ring of the left input socket 11; the input end and the output end of the left secondary coil are respectively connected to the central core hole and the grounding ring of the left output socket 31; The right isolation transformer 22 includes a right iron core, with a right primary coil and a right secondary coil wound on both sides of the right iron core respectively. The input end and output end of the right primary coil are respectively connected to the central core hole and the outer ring of the right input socket 22; the input end and output end of the right secondary coil are respectively connected to the central core hole and the grounding ring of the right output socket 32.

[0047] The audio signal is input from the left input socket 11, passes through the left isolation transformer 21, and finally outputs from the left output socket 31, forming the left channel of the audio signal transmission; the audio signal is input from the right input socket 12, passes through the right isolation transformer 22, and finally outputs from the right output socket 32, forming the right channel of the audio signal transmission. The left channel and the right channel together form a left and right dual-channel mode.

[0048] Among them, when the left input socket 11, the left isolation transformer 21 and the left channel of the left output socket 31 exist alone, it is the monaural mode of Example 1; when the right input socket 12, the right isolation transformer 22 and the right output socket 32 ​​exist alone, it is also the monaural mode of Example 1.

[0049] In order to ensure the synchronization of audio signal transmission in the left channel mode and the audio signal transmission in the right channel mode, preferably, the output end of the left primary coil is connected to the output end of the right primary coil; the output end of the left secondary coil is connected to the output end of the right secondary coil, thereby changing the state when the left and right dual channels in the dual channel mode are separated into the state when the left and right dual channels are integrated, such as Figure 3 shown.

[0050] Specifically, the output end of the left primary coil, the output end of the right primary coil, and the grounding ring of the left input socket 11 and the grounding ring of the right input socket 12 are at the same potential.

[0051] In order to dock the pickup, the pickup is configured with a left audio output plug and a right audio output plug, both of which are RCA plugs, including a central terminal and a grounding ring around it. When the left audio output plug and the right audio output plug of the pickup are respectively inserted into the left input socket 11 and the right input socket 12 of the audio input part 1, the central terminal of the left audio output plug of the pickup is just inserted into the central ferrule hole of the left input socket 11 of the audio input part 1, and the grounding ring of the left audio output plug of the pickup is in contact with the grounding ring of the left input socket 11 of the audio input part 1; at the same time, the central terminal of the right audio output plug of the pickup is just inserted into the central ferrule hole of the right input socket 12 of the audio input part 1, and the grounding ring of the right audio output plug of the pickup is in contact with the grounding ring of the right input socket 12 of the audio input part 1.

[0052] Since the grounding rings of the left and right audio output plugs of the microphone are usually connected to the ground wire, it can be considered that the output end of the left primary coil, the output end of the right primary coil, and the grounding rings of the left input socket 11 and the grounding rings of the right input socket 12 are all at zero potential, that is, they are all grounded.

[0053] In order to connect the audio output device, the audio output device is configured with a left audio input plug and a right audio input plug, and the left audio output plug and the right audio output plug are both RCA plugs, including a central terminal and a grounding ring around it. When the left audio input plug and the right audio input plug of the audio output device are respectively inserted into the left output socket 31 and the right output socket 32 ​​of the audio output part 3, The central terminal of the left audio input plug of the audio output device is just inserted into the central ferrule hole of the left output socket 31 of the audio output part 3, and the grounding ring sheet of the left audio input plug of the audio output device is in contact with the grounding ring ring of the left output socket 31 of the audio output part 3; at the same time, the central terminal of the right audio input plug of the audio output device is just inserted into the central ferrule hole of the right output socket 32 ​​of the audio output part 3, and the grounding ring sheet of the right audio input plug of the audio output device is in contact with the grounding ring ring of the right output socket 32 ​​of the audio output part 3.

[0054] Specifically, the output end of the left secondary coil, the output end of the right secondary coil, and the grounding ring of the left output socket 31 and the grounding ring of the right output socket 32 ​​are at the same potential, but are not grounded.

[0055] Example 4: Mixed Stereo Channel Mode On the basis of Example 1, Example 4 provides an audio isolation device for implementing a mixed stereo channel mode, and its circuit structure is described in detail below in conjunction with the accompanying drawings.

[0056] refer to Figure 3 The audio input part 1 of the audio isolation device includes a stereo input socket 10, which is an RCA interface, including a central ferrule hole and a grounding ring outside thereof; The audio output unit 3 includes a stereo output socket 30, which is an RCA interface, including a central ferrule hole and a grounding ring outside thereof; The audio isolation circuit 2 includes a left isolation transformer 21 and a right isolation transformer 22. The stereo input socket 10 is connected to the stereo output socket 30 through the left isolation transformer 21 and the right isolation transformer 22, respectively, so as to form a mixed stereo channel mode.

[0057] In order to ensure the synchronization of the audio signal being transmitted from the stereo input socket 10 to the stereo output socket 30 through the left isolation transformer 21 and the right isolation transformer 22 respectively, the output end of the left primary coil is connected to the output end of the right primary coil; the output end of the left secondary coil is connected to the output end of the right secondary coil.

[0058] Specifically, the left isolation transformer 21 includes a left core, and a left primary coil and a left secondary coil are respectively wound on both sides of the left core, and the input end and the output end of the left primary coil are respectively connected to the central ferrule hole and the grounding ring of the stereo input socket 10; the input end and the output end of the left secondary coil are respectively connected to the central ferrule hole and the grounding ring of the stereo input socket 10; The right isolation transformer 22 includes a right iron core, with a right primary coil and a right secondary coil wound on both sides of the right iron core respectively. The input end and output end of the right primary coil are respectively connected to the central core hole and the outer ring of the stereo output socket 30; the input end and output end of the right secondary coil are respectively connected to the central core hole and the grounding ring of the stereo output socket 30.

[0059] More specifically, the stereo input socket 10 is configured with an input signal wiring frame, and the center ferrule hole of the stereo input socket 10, the input end of the left primary coil and the input end of the right primary coil are all connected to the input signal wiring frame; the stereo output socket 30 is configured with an output signal wiring frame, and the center ferrule hole of the stereo output socket 30, the input end of the right primary coil and the input end of the right secondary coil are all connected to the output signal wiring frame.

[0060] Specifically, the stereo input socket 10 and the stereo output socket 30 are both coaxial audio interfaces with an inner diameter of 3.5 mm.

[0061] Example 5: Mode of left and right dual channels and mixed stereo channels Embodiment 5 of the present invention provides an audio isolation device in a mode of combining left and right dual channels and mixed stereo channels, which is essentially a combination of Embodiment 3 and Embodiment 4. Its circuit structure is described in detail below in conjunction with the accompanying drawings.

[0062] refer to Figure 4 The audio isolation device is based on the audio isolation device of Example 4, and adds the technical features of Example 3: the audio input part 1 also includes a left input socket 11 and a right input socket 12, and the left input socket 11 and the right input socket 12 are both RCA interfaces, including a central ferrule hole and a grounding ring outside thereof; The audio output unit 3 further includes a left output socket 31 and a right output socket 32. Both the left output socket 31 and the right output socket 32 ​​are RCA interfaces, including a central ferrule hole and a grounding ring outside thereof. The input end and output end of the left primary coil of the left isolation transformer 21 are respectively connected to the central ferrule hole and the grounding ring of the left input socket 11, and the input end and output end of the left secondary coil are respectively connected to the central ferrule hole and the grounding ring of the left output socket 31; The input and output ends of the right primary coil of the right isolation transformer 22 are respectively connected to the central ferrule hole and outer ring of the right input socket 22, and the input and output ends of the right secondary coil are respectively connected to the central ferrule hole and grounding ring of the right output socket 32.

[0063] Specifically, the left isolation transformer 21 and the right isolation transformer 22 are both 10K:10K Permalloy transformers.

[0064] The main parameters of the audio isolation device: Frequency bandwidth: 20Hz~20KHz; Isolation voltage: AC50Hz~60Hz 0~1500V; Input impedance: 10K ohms; Output impedance: 10K ohms.

[0065] Embodiment 6: An audio isolation circuit Embodiment 6 of the present invention provides an audio isolation circuit, which serves as the audio isolation circuit 2 in the audio isolation device when the left and right channels are integrated in Embodiment 3 to the audio isolation device in Embodiment 5. The circuit structure thereof is described in detail below in conjunction with the accompanying drawings.

[0066] refer to Figure 6 The audio isolation circuit includes a left isolation transformer 21 and a right isolation transformer 22. The left isolation transformer 21 comprises a left iron core, and a left primary coil and a left secondary coil are respectively wound on two sides of the left iron core; The right isolation transformer 22 comprises a right iron core, and a right primary coil and a right secondary coil are respectively wound on two sides of the right iron core; The output terminal O1 of the left primary coil is connected to the output terminal O2 of the right primary coil; The output terminal O'1 of the left secondary coil is connected to the output terminal O'2 of the right secondary coil.

[0067] Among them, when the audio isolation circuit is configured with a left input socket 11, a left output socket 31, a right input socket 12 and a right output socket 32, and the input end I1 and the output end O1 of the left primary coil of the left isolation transformer 21 are respectively connected to the central ferrule hole and the grounding ring of the left input socket 11, and the input end I'1 and the output end O'1 of the left secondary coil of the left isolation transformer 21 are respectively connected to the central ferrule hole and the grounding ring of the left output socket 31; the input end I2 and the output end O2 of the right primary coil of the right isolation transformer 22 are respectively connected to the central ferrule hole and the grounding ring of the right input socket 12, and the input end I'2 and the output end O'2 of the right secondary coil of the right isolation transformer 22 are connected to the central ferrule hole and the grounding ring of the right output socket 32, the audio isolation device for left and right dual-channel integration of Example 3 is formed, as shown in FIG. Figure 3 shown.

[0068] When the audio isolation circuit is configured with a stereo input socket 10 and a stereo output socket 30, and the input end and the output end of the left primary coil of the left isolation transformer 21 are respectively connected to the central ferrule hole and the grounding ring of the stereo input socket 10, and the input end and the output end of the left secondary coil are respectively connected to the central ferrule hole and the grounding ring of the stereo input socket 10; the input end and the output end of the right primary coil of the right isolation transformer 22 are respectively connected to the central ferrule hole and the outer ring of the stereo output socket 30, and the input end and the output end of the right secondary coil are respectively connected to the central ferrule hole and the grounding ring of the stereo output socket 30, the audio isolation device of the mixed stereo channel mode of embodiment 4 is formed, as shown in FIG. Figure 4 shown.

[0069] When the audio isolation circuit is equipped with a left input socket 11, a left output socket 31, a right input socket 12 and a right output socket 32, as well as a stereo input socket 10 and a stereo output socket 30, and is wired according to the circuits of Embodiments 3 and 4, an audio isolation device of a mode of left and right dual channels and a mixed stereo channel combination of Embodiment 5 is formed, as shown in FIG. Figure 5 shown.

[0070] Embodiment 7: A method for using an audio isolation device The audio isolation device of the left and right dual channels and the mixed stereo channel combination mode of embodiment 5 is adopted, wherein the audio input part 1 of the audio isolation device is externally connected to the microphone of the surveillance camera, and embodiment 7 provides a method for using the audio isolation device, comprising the following steps: The pickup converts the sound signal into an electrical signal, and the electrical signal passes through the audio input unit 1 as an audio input signal; The stereo input socket 10 alone or the left input socket 11 and the right input socket 12 simultaneously receive audio input signals; The audio input signal is simultaneously transmitted to the primary coils of the left isolation transformer 21 and / or the right isolation transformer 22, and the iron cores of the left isolation transformer 21 and / or the right isolation transformer 22 simultaneously generate left alternating magnetic flux and / or right alternating magnetic flux respectively; The left alternating magnetic flux passes through the primary coil and the secondary coil of the left isolation transformer 21, and generates an induced electromotive force in both the primary coil and the secondary coil of the left isolation transformer 21, and / or the right alternating magnetic flux passes through the primary coil and the secondary coil of the right isolation transformer 22, and generates an induced electromotive force in both the primary coil and the secondary coil of the right isolation transformer 22; The iron core of the left isolation transformer 21 converts the voltage and current on the primary coil side into the voltage and current on the secondary coil side through electromagnetic induction, and / or the iron core of the right isolation transformer 22 converts the voltage and current on the primary coil side into the voltage and current on the secondary coil side through electromagnetic induction; The voltage and current on the secondary coil side of the left isolation transformer 21 and / or the right isolation transformer 22 are outputted through the stereo output socket 30 in the audio output unit 3 alone or through the left output socket 31 and the right output socket 32 ​​simultaneously to form an audio output signal.

[0071] Among them, in the process of converting the audio output signal and the audio input signal through the isolation transformer, not only can the high-frequency loss characteristics of the iron core of the isolation transformer avoid the interference of external signals on the audio signal, but also because the primary coil and the secondary coil are completely disconnected, that is, the electrical connection is isolated, it can filter the electrical impact of the external environment on the audio signal, further prevent external interference, and finally achieve the isolation of the audio signal from external noise.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An audio isolation device for a surveillance camera, characterized in that: include: An audio input unit (1), comprising 1 to 3 audio input interfaces, used for connecting to a microphone of an external surveillance camera; An audio output unit (3), comprising 1 to 3 audio output interfaces for connecting to an external audio output device; The audio isolation circuit (2) comprises 1 to 2 isolation transformers, wherein the primary coil and the secondary coil of each isolation transformer are respectively connected to the input interface of the audio input part (1) and the output interface of the audio output part (3) via signal lines, respectively forming a mono mode, a left and right dual channel mode, a mixed stereo channel mode, and a mode combining left and right dual channel and mixed stereo channel; In any one of the monophonic mode, left and right dual-channel mode, mixed stereophonic channel mode, and the left and right dual-channel and mixed stereophonic channel combination mode, during the process of the audio output signal and the audio input signal being transformed through the isolation transformer, the isolation transformer of the audio isolation circuit (2) can isolate the audio input signal from the audio output signal to avoid signal interference and loss.

2. The audio isolation device for a surveillance camera according to claim 1, characterized in that: The isolation transformer comprises an iron core, and the windings of the primary coil and the secondary coil on the iron core are the same; The audio input interface of the audio input part (1) receives an audio input signal, and the audio output interface of the audio output part (3) outputs an audio output signal. When the audio input signal and the audio output signal are transformed through the audio isolation circuit (2), the high-frequency loss characteristics of the iron core of the isolation transformer can prevent external signals from interfering with the audio signal, and the isolated electrical connection between the primary coil and the secondary coil can filter the electrical impact of the external environment on the audio signal, further preventing external interference, and finally achieving isolation of the audio signal from external noise.

3. The audio isolation device for a surveillance camera according to claim 1, characterized in that: The audio input part (1) comprises an input socket, the input socket comprises a central ferrule hole, and a grounding ring is arranged on the outer periphery of the central ferrule hole; The audio output part (3) comprises an output socket, the output socket comprises a central ferrule hole, and a grounding ring is arranged on the outer periphery of the central ferrule hole; The audio isolation circuit (2) comprises an isolation transformer, the isolation transformer comprises an iron core, and two sides of the iron core are respectively wound with a primary coil (L1) and a secondary coil (L2); The input end of the primary coil (L1) is connected to the central plug hole of the input socket of the audio input part (1), and the output end of the primary coil (L1) is connected to the grounding ring of the input socket of the audio input part (1); The input end of the secondary coil (L2) is connected to the central plug hole of the output socket of the audio output part (3), and the output end of the secondary coil (L2) is connected to the grounding ring of the output socket of the audio output part (3).

4. The audio isolation device for a surveillance camera according to claim 1, characterized in that: The audio input part (1) comprises a left input socket (11) and a right input socket (12), wherein the left input socket (11) and the right input socket (12) both comprise a central ferrule hole and a grounding ring outside thereof; The audio output part (3) comprises a left output socket (31) and a right output socket (32), and the left output socket (31) and the right output socket (32) both comprise a central ferrule hole and a grounding ring outside thereof; The audio isolation circuit (2) comprises a left isolation transformer (21) and a right isolation transformer (22). The left isolation transformer (21) comprises a left iron core, with a left primary coil and a left secondary coil respectively wound on both sides of the left iron core, the input end and the output end of the left primary coil respectively connected to the central core insertion hole and the grounding ring of the left input socket (11); the input end and the output end of the left secondary coil respectively connected to the central core insertion hole and the grounding ring of the left output socket (31); The right isolation transformer (22) comprises a right iron core, with a right primary coil and a right secondary coil respectively wound on both sides of the right iron core, the input end and the output end of the right primary coil respectively connected to the central core hole and the outer ring of the right input socket (22); the input end and the output end of the right secondary coil respectively connected to the central core hole and the grounding ring of the right output socket (32).

5. The audio isolation device for a surveillance camera according to claim 4, characterized in that: The output end of the left primary coil is connected to the output end of the right primary coil; the output end of the left secondary coil is connected to the output end of the right secondary coil.

6. The audio isolation device for a surveillance camera according to claim 1, characterized in that: The audio input part (1) comprises a stereo input socket (10), and the stereo input socket (10) comprises a central ferrule hole and a grounding ring outside thereof; The audio output part (3) comprises a stereo output socket (30), and the stereo output socket (30) comprises a central ferrule hole and a grounding ring outside thereof; The audio isolation circuit (2) comprises a left isolation transformer (21) and a right isolation transformer (22), and the stereo input socket (10) is connected to the stereo output socket (30) via the left isolation transformer (21) and the right isolation transformer (22), respectively.

7. The audio isolation device for a surveillance camera according to claim 6, characterized in that: The left isolation transformer (21) comprises a left iron core, with a left primary coil and a left secondary coil respectively wound around two sides of the left iron core, the input end and the output end of the left primary coil respectively connected to the central core hole and the grounding ring of the stereo input socket (10); the input end and the output end of the left secondary coil respectively connected to the central core hole and the grounding ring of the stereo input socket (10); The right isolation transformer (22) comprises a right iron core, with a right primary coil and a right secondary coil respectively wound around two sides of the right iron core, the input end and the output end of the right primary coil respectively connected to the central core insertion hole and the outer ring of the stereo output socket (30); the input end and the output end of the right secondary coil respectively connected to the central core insertion hole and the grounding ring of the stereo output socket (30).

8. The audio isolation device for a surveillance camera according to claim 7, characterized in that: The audio input part (1) further comprises a left input socket (11) and a right input socket (12), wherein the left input socket (11) and the right input socket (12) both comprise a central ferrule hole and a grounding ring outside thereof; The audio output unit (3) further comprises a left output socket (31) and a right output socket (32), wherein the left output socket (31) and the right output socket (32) both comprise a central ferrule hole and a grounding ring outside thereof; The input end and the output end of the left primary coil of the left isolation transformer (21) are respectively connected to the central core hole and the grounding ring of the left input socket (11), and the input end and the output end of the left secondary coil are respectively connected to the central core hole and the grounding ring of the left output socket (31); The input end and the output end of the right primary coil of the right isolation transformer (22) are respectively connected to the central core hole and the outer ring of the right input socket (22), and the input end and the output end of the right secondary coil are respectively connected to the central core hole and the grounding ring of the right output socket (32).

9. The audio isolation circuit in the audio isolation device according to any one of claims 5 to 8, characterized in that: It includes a left isolation transformer (21) and a right isolation transformer (22), The left isolation transformer (21) comprises a left iron core, with a left primary coil and a left secondary coil respectively wound on two sides of the left iron core; the right isolation transformer (22) comprises a right iron core, with a right primary coil and a right secondary coil respectively wound on two sides of the right iron core; The output end (O1) of the left primary coil is connected to the output end (O2) of the right primary coil, and the output end (O'1) of the left secondary coil is connected to the output end (O'2) of the right secondary coil, forming the audio isolation circuit.

10. A method for using an audio isolation device, using the audio isolation device according to claim 8, wherein the audio input portion (1) of the audio isolation device is externally connected to a microphone of a surveillance camera, characterized in that: include: The microphone converts the sound signal into an electrical signal, and the electrical signal is passed through the audio input part (1) as an audio input signal; The stereo input socket (10) receives the audio input signal alone or the left input socket (11) and the right input socket (12) simultaneously; The audio input signal is simultaneously transmitted to the primary coil of the left isolation transformer (21) and / or the right isolation transformer (22), and the iron cores of the left isolation transformer (21) and / or the right isolation transformer (22) respectively generate left alternating magnetic flux and / or right alternating magnetic flux simultaneously; The left alternating magnetic flux passes through the primary coil and the secondary coil of the left isolation transformer (21), and generates an induced electromotive force in both the primary coil and the secondary coil of the left isolation transformer (21), and / or the right alternating magnetic flux passes through the primary coil and the secondary coil of the right isolation transformer (22), and generates an induced electromotive force in both the primary coil and the secondary coil of the right isolation transformer (22); The iron core of the left isolation transformer (21) converts the voltage and current on the primary coil side into the voltage and current on the secondary coil side through electromagnetic induction, and / or the iron core of the right isolation transformer (22) converts the voltage and current on the primary coil side into the voltage and current on the secondary coil side through electromagnetic induction; The voltage and current on the secondary coil side of the left isolation transformer (21) and / or the right isolation transformer (22) are outputted through the stereo output socket (30) in the audio output unit (3) individually or through the left output socket (31) and the right output socket (32) simultaneously to form an audio output signal; Among them, in the process of converting the audio output signal and the audio input signal through the isolation transformer, not only can the high-frequency loss characteristics of the iron core of the isolation transformer avoid the interference of external signals on the audio signal, but also because the primary coil and the secondary coil are isolated and electrically connected, the electrical impact of the external environment on the audio signal can be filtered, further preventing external interference, and finally achieving the isolation of the audio signal from external noise.

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