An antenna audio hybrid coaxial shielded wire based on intelligent combining and splitting circuit

Abstract

The application discloses an antenna audio hybrid coaxial shielded wire based on an intelligent distribution and combination circuit and belongs to the field of communication audio transmission. One end of the wire is provided with the intelligent distribution and combination circuit, which comprises a high-frequency channel, an audio channel and a signal separation module. The module identifies signal frequency characteristics in real time, dynamically shunts two types of signals to corresponding channels, high-frequency signals are transmitted through an outer conductor shielding layer, and audio signals are transmitted through an inner conductor. The outer conductor shielding layer is provided with a switching switch, which can be connected to a radio frequency ground or an audio ground of a intercom as required: the radio frequency ground is connected when high-frequency signals are transmitted, and the antenna ground is used as a reference; the audio ground is connected when audio signals are transmitted, and an audio return path is formed. The application combines the physical shunting of the coaxial cable double conductor and the dynamic switching of the intelligent circuit, integrates the antenna and the earphone cable into one, and effectively isolates the crosstalk interference between the high-frequency and audio signals.

Description

Technical Field

[0001] This invention relates to the field of communication and audio transmission technology, specifically to an antenna-audio composite coaxial shielded wire based on an intelligent split-combiner circuit, used for integrating antenna and audio transmission functions in a walkie-talkie system. Background Technology

[0002] Walkie-talkies, as a widely used wireless communication device, play an irreplaceable role in security, construction, emergency rescue, and outdoor activities. Traditional walkie-talkies require two separate cables when using an external headset: an antenna cable for transmitting and receiving radio frequency signals, and a headset cable for transmitting audio signals. This separate cable configuration results in a complex external wiring structure and a large number of cables, which are prone to tangling and getting stuck during use, affecting user convenience and communication experience.

[0003] To simplify the external wiring structure of walkie-talkies, existing technologies have proposed integrating the headphone cable with the antenna function. Sony Corporation of Japan's headphone antenna technology (CN200480005195.3) uses a combination of a balanced-to-unbalanced converter and an inductor coil, enabling the audio / high-frequency dual-function signal line to simultaneously perform the dual functions of antenna reception and audio transmission. This solution incorporates a complex separation and superposition circuit between the headphone cable and the antenna, achieving frequency-selective impedance variation through the inductor coil. Another headphone antenna technology (CN200610064769) uses the core wire of a coaxial cable and shielding circuitry to construct the antenna, and includes a separation and superposition circuit section. It utilizes a high-frequency choke and a chip capacitor to achieve the separation and superposition of radio frequency and audio signals.

[0004] While the aforementioned existing technology achieves the integration of headphone cable and antenna functions, it has the following shortcomings: 1. The separate superimposed circuit structure is complex and requires the use of multiple high-frequency chokes and capacitors, which increases the circuit size and cost.

[0005] 2. Signal separation relies on the combination of multiple discrete components. The parameter matching between the components is strictly required. Temperature drift and component aging can easily lead to a decrease in separation performance.

[0006] 3. The antenna function and audio transmission function are not truly multiplexed in the physical path, but are achieved through superposition and separation at the circuit level, resulting in additional insertion loss in the signal path.

[0007] 4. In the existing scheme, the outer conductor shielding layer of the coaxial cable is always fixed to the ground and is only used as an electromagnetic shielding structure. The possibility of it playing different functional roles in high-frequency and audio dual-mode operation is not considered.

[0008] To address the aforementioned issues, this invention proposes an antenna-audio composite coaxial shielded wire based on an intelligent split-combiner circuit. Through the coordinated action of the physical current splitting of the coaxial shielded wire's two conductors and the frequency-selective separation of the intelligent split-combiner circuit, the functions of an antenna and an earphone cable are combined into one, while simultaneously eliminating mutual interference between high-frequency signals and audio signals. Summary of the Invention

[0009] The purpose of this invention is to provide an antenna audio composite coaxial shielded wire based on an intelligent split-combination circuit, so as to solve the technical problems of complex external wiring structure of walkie-talkies, large number of cables due to separate antenna and earphone wire settings, and complex circuit and insufficient signal separation performance of existing integrated solutions in the prior art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: An antenna audio composite coaxial shielded conductor based on an intelligent split-and-combination circuit includes a coaxial shielded composite conductor and an intelligent split-and-combination circuit. The coaxial shielded composite conductor has an inner conductor, an insulating layer covering the outer periphery of the inner conductor, an outer conductor shielding layer covering the outer periphery of the insulating layer, and an outer sheath covering the outer periphery of the outer conductor shielding layer. The outer conductor shielding layer serves as the high-frequency signal transmission and radiation channel for a walkie-talkie antenna, the inner conductor serves as the audio signal transmission channel for an earphone speaker, and the outer conductor shielding layer also serves as a grounding loop for the audio signal during audio transmission. The intelligent split-and-combination circuit is connected to the first end of the coaxial shielded composite conductor and includes a high-frequency signal channel, an audio signal channel, and a signal separation module. The signal separation module is connected to both the high-frequency signal channel and the audio signal channel.

[0011] The signal separation module detects the frequency characteristics of the signals transmitted in the outer conductor shielding layer in real time. Based on the frequency characteristics, it dynamically routes high-frequency signals to high-frequency signal channels and audio signals to audio signal channels, so that the outer conductor shielding layer works as an antenna radiator in the high-frequency signal state and as an audio grounding loop in the audio signal state.

[0012] The outer conductor shielding layer is connected to both the radio frequency (RF) ground and audio ground of the walkie-talkie via a switch, with the RF ground and audio ground being set independently. In high-frequency mode, the switch connects the outer conductor shielding layer to the RF ground of the walkie-talkie, making the outer conductor shielding layer serve as the antenna ground reference plane; in audio mode, the switch connects the outer conductor shielding layer to the audio ground of the walkie-talkie, making the outer conductor shielding layer serve as the audio signal grounding loop.

[0013] The signal separation module includes a high-pass filter unit and a low-pass filter unit. The input of the high-pass filter unit is connected to the outer conductor shielding layer, and its output is connected to the high-frequency signal channel. The input of the low-pass filter unit is connected to the inner conductor, and its output is connected to the audio signal channel. The high-pass filter unit consists of a series capacitor and a parallel inductor, and its cutoff frequency is set between the lower limit of the walkie-talkie's operating frequency band and the highest frequency of the audio signal. The low-pass filter unit consists of a series inductor and a parallel capacitor, and its cutoff frequency is set between the highest frequency of the audio signal and the lower limit of the walkie-talkie's operating frequency band. Through the coordinated operation of the high-pass and low-pass filter units, the high-frequency signal is guided to the high-frequency signal channel, and the audio signal is guided to the audio signal channel, achieving physical separation of the two signals on different conductors.

[0014] The intelligent splitter / combiner circuit also includes an impedance matching unit, which is connected between the signal separation module and the high-frequency signal channel. The impedance matching unit converts the output impedance of the walkie-talkie's RF end to an impedance value that matches the characteristic impedance of the coaxial shielded composite conductor. The impedance matching unit is either a π-type resistor attenuation network or an L-type LC matching network. The input impedance of the impedance matching unit is equal to the output impedance of the walkie-talkie's RF end, and the output impedance is equal to the characteristic impedance of the coaxial shielded composite conductor. By configuring the impedance matching unit, the reflection loss of the high-frequency signal during transmission is minimized, ensuring antenna radiation efficiency.

[0015] The intelligent splitting and combining circuit also includes an audio isolation unit, which is connected between the signal separation module and the audio signal channel. The audio isolation unit suppresses high-frequency residual components in the audio signal channel. The audio isolation unit is a common-mode choke or ferrite bead, exhibiting low impedance in the audio frequency band and high impedance in the walkie-talkie operating frequency band. The audio isolation unit further filters out high-frequency residual signals that may leak into the audio channel, ensuring that the audio signal is not subject to high-frequency interference.

[0016] The second end of the coaxial shielded composite conductor is connected to a Type-C connector. The Type-C connector includes pins CC1, CC2, D+, D-, VBUS, and GND. The inner conductor is connected to at least one of the D+ and D- pins, and the outer conductor shielding layer is connected to the GND pin. The GND pin is connected to the ground of the walkie-talkie PCB circuit board via an isolation component. In audio transmission mode, the outer conductor shielding layer serves as a grounding loop for the audio signal; in high-frequency transmission mode, it serves as a grounding reference surface for the antenna radiator, achieving dual-mode multiplexing of the shielding layer.

[0017] The length of the coaxial shielded composite wire is set to an integer multiple of one-quarter of the wavelength corresponding to the center frequency of the walkie-talkie's operating frequency band, causing the coaxial shielded composite wire to exhibit resonant antenna characteristics within the walkie-talkie's operating frequency band. By setting the length, the coaxial shielded composite wire forms a standing wave distribution within the walkie-talkie's operating frequency band, and the current distribution on the outer conductor shielding layer meets the antenna radiation conditions, thus realizing the antenna function.

[0018] The intelligent split-connect circuit is integrated into the Type-C port circuit board of the walkie-talkie or into an external adapter. The power supply for the intelligent split-connect circuit is provided by the internal power supply circuit of the walkie-talkie. When the intelligent split-connect circuit is integrated into an external adapter, the adapter connects to the walkie-talkie via its Type-C port. The adapter integrates a signal separation module, impedance matching unit, and audio isolation unit. One end of the external adapter connects to a coaxial shielded composite cable, and the other end connects to the Type-C port of the walkie-talkie.

[0019] The intelligent switching circuit described in this invention dynamically switches the paths of high-frequency signals and audio signals according to the following working method when performing signal transmission: Step S1, Signal Detection Step: The intelligent splitting and combining circuit uses the frequency detection subunit in the signal separation module to detect the frequency characteristics of the signal transmitted on the outer conductor shielding layer in real time. When there is a signal output from the radio frequency terminal of the walkie-talkie, the signal separation module detects that the signal frequency is within the operating frequency band of the walkie-talkie and determines it to be a high-frequency signal; when there is a signal output from the audio circuit of the walkie-talkie, the signal separation module detects that the signal frequency is within the audio frequency band and determines it to be an audio signal.

[0020] Step S2, Path Selection Step: When the signal separation module determines that the signal is a high-frequency signal, the high-pass filter unit is turned on, and the low-pass filter unit is turned off. The high-frequency signal enters the high-frequency signal channel through the high-pass filter unit, and after impedance transformation by the impedance matching unit, it is transmitted to the walkie-talkie's RF terminal. When the signal separation module determines that the signal is an audio signal, the low-pass filter unit is turned on, and the high-pass filter unit is turned off. The audio signal enters the audio signal channel through the low-pass filter unit, and after the audio isolation unit filters out high-frequency residual components, it is transmitted to the earphone speaker.

[0021] Step S3, Shielding Layer Switching Step: The intelligent switching circuit synchronously controls the grounding connection mode of the outer conductor shielding layer through the switch control subunit according to the current operating state. In high-frequency state, the outer conductor shielding layer is connected to the walkie-talkie's RF ground through the switching switch, making the outer conductor shielding layer serve as the grounding reference surface of the antenna radiator, providing a stable reference potential for the antenna. In audio state, the outer conductor shielding layer is connected to the walkie-talkie's audio ground through the switching switch, making the outer conductor shielding layer serve as the grounding loop for the audio signal, providing a low-impedance return path for the audio signal.

[0022] The above three steps are executed sequentially in time, forming a complete signal routing loop. When high-frequency signals and audio signals exist simultaneously, the signal separation module performs path selection in parallel based on the frequency characteristics of the signals. The high-frequency signal enters the high-frequency signal channel through the high-pass filter unit and is transmitted through the outer conductor shielding layer, while the audio signal enters the audio signal channel through the low-pass filter unit and is transmitted through the inner conductor. The two signals are transmitted separately on different conductors of the coaxial shielded composite wire without interfering with each other.

[0023] The working principle of this invention is as follows: In transmit mode, the high-frequency signal generated by the walkie-talkie's radio frequency (RF) terminal enters the signal separation module via the high-frequency signal channel. The high-pass filter unit in the signal separation module allows the high-frequency signal to pass through, while the low-pass filter unit prevents it from entering the audio signal channel. After impedance transformation by the impedance matching unit, the high-frequency signal is transmitted through the outer conductor shielding layer to the far end of the coaxial shielded composite conductor. The length of the coaxial shielded composite conductor is set to an integer multiple of one-quarter of the wavelength corresponding to the operating frequency band. The high-frequency current on the outer conductor shielding layer forms a standing wave distribution, enabling the coaxial shielded composite conductor to radiate electromagnetic waves into space as an antenna radiator. In high-frequency mode, the outer conductor shielding layer is connected to the walkie-talkie's RF ground via a switching switch, forming the ground reference surface of the antenna radiator.

[0024] In receive mode, spatial electromagnetic waves induce high-frequency signals on the coaxial shielded composite conductor. These high-frequency signals are transmitted through the outer conductor shielding layer to the intelligent switching circuit, then through a high-pass filter unit into the high-frequency signal channel, and finally transmitted to the walkie-talkie's radio frequency (RF) terminal for demodulation. In receive mode, the outer conductor shielding layer is connected to the walkie-talkie's RF ground via a switching switch to ensure the integrity of the received signal.

[0025] In audio transmission mode, the audio signal generated by the walkie-talkie's audio circuit enters the signal separation module via the audio signal channel. The low-pass filter in the signal separation module allows the audio signal to pass through, while the high-pass filter prevents it from entering the high-frequency signal channel. The audio signal is transmitted through the inner conductor to the far end of the coaxial shielded composite conductor, driving the headset speaker to produce sound through the Type-C connector. In audio mode, the outer conductor shielding layer is connected to the walkie-talkie's audio ground via a switch, serving as a grounding loop for the audio signal. The audio isolation unit further suppresses high-frequency residual components that may couple into the audio channel, ensuring the purity of the audio signal.

[0026] In this invention, the outer conductor shielding layer of the coaxial shielded composite wire carries high-frequency signals, while the inner conductor carries audio signals. Under the frequency-selective separation of the intelligent splitter circuit, the two signals propagate along predetermined paths without interference. The outer conductor shielding layer of the coaxial shielded composite wire serves as the antenna ground reference surface in high-frequency mode and as the audio signal grounding loop in audio mode, achieving dual-mode multiplexing of the shielding layer. The physical structure multiplexing of the coaxial shielded composite wire and the frequency-selective separation of the intelligent splitter circuit mutually support each other, together forming a complete signal transmission and radiation system.

[0027] Compared with the prior art, the present invention has the following advantages: First, by using the outer conductor shielding layer of the coaxial shielded composite wire to carry high-frequency signals and the inner conductor to carry audio signals, the functions of the antenna and the headphone wire are combined into one. This simplifies the external wiring structure and reduces the number of cables by merging the antenna wire and headphone wire in the traditional walkie-talkie external wiring into a single coaxial shielded composite wire.

[0028] Secondly, through the dual isolation of physical current splitting by two conductors and frequency separation by intelligent splitting and combining circuits, high-frequency signals and audio signals are physically separated on the transmission path, eliminating mutual interference between high-frequency signals and audio signals, and ensuring antenna radiation efficiency and audio transmission quality.

[0029] Third, by matching the impedance of the RF end with the characteristic impedance of the coaxial shielded composite wire through the impedance matching unit, the reflection loss during high-frequency signal transmission is reduced and the antenna radiation efficiency is improved.

[0030] Fourth, the audio isolation unit further suppresses high-frequency residual components in the audio channel, ensuring the purity of the audio signal and improving the signal-to-noise ratio of the audio output.

[0031] Fifth, the technical effects produced by this invention go beyond the simple summation of the individual effects of each technical feature, specifically manifested in the following technical effects: (I) The outer conductor shielding layer represents a qualitative leap from a passive shielding structure to an active functional element. In existing technologies, the outer conductor shielding layer of a coaxial shielded cable is always fixedly grounded, serving only as an electromagnetic shielding structure, with a single and passive function. In this invention, the outer conductor shielding layer is connected to both the walkie-talkie's radio frequency (RF) ground and audio ground via a switching switch, with the RF ground and audio ground being independently configured. In high-frequency mode, the outer conductor shielding layer switches to connect to the walkie-talkie's RF ground, serving as the antenna ground reference surface, directly affecting the antenna's radiation efficiency and the stability of its radiation pattern; in audio mode, the outer conductor shielding layer switches to connect to the walkie-talkie's audio ground, serving as the audio signal grounding loop, directly affecting the audio signal return path and signal-to-noise ratio. The shielding layer transforms from a passive shielding tool into an active functional switching element, with its functional role dynamically changing according to the operating state.

[0032] (II) Coordinated Dynamic Configuration of Signal Path and Shielding Layer Grounding Method. In this invention, the signal separation module detects the frequency characteristics of the signal transmitted in the outer conductor shielding layer in real time. Based on these frequency characteristics, it dynamically routes high-frequency signals to the high-frequency signal channel and audio signals to the audio signal channel, while simultaneously controlling the grounding connection method of the outer conductor shielding layer. Changes in signal type trigger signal path switching, which in turn triggers shielding layer grounding method switching. These three actions (signal detection, path selection, and shielding layer switching) are executed synchronously in time and support each other functionally. This system-level coordinated behavior ensures that the invention maintains optimal matching between the signal path and shielding layer function under any operating state. In the prior art, the signal path remains fixed, and the shielding layer is always fixedly grounded, with no coordinated relationship between the two. The coordinated dynamic configuration of this invention is not a simple superposition of the individual effects of each technical feature, but a qualitative change resulting from their combination.

[0033] (III) Eliminates the systemic risk of high-frequency signals coupling to the audio circuit through the shielding layer. In existing technologies, the shielding layer is fixedly grounded, and the return path of the high-frequency signal and the grounding path of the audio signal share the same grounding point. The risk of high-frequency signals coupling to the audio circuit through the shielding layer always exists. In this invention, the walkie-talkie's radio frequency ground and audio ground are set independently, and electrical isolation between them is achieved through isolation components. In high-frequency mode, the outer conductor shielding layer is connected to the walkie-talkie's radio frequency ground through a switch, and the return path of the high-frequency signal only passes through the radio frequency ground; in audio mode, the outer conductor shielding layer is connected to the walkie-talkie's audio ground through a switch, and the grounding path of the audio signal only passes through the audio ground. The physical separation of the radio frequency ground and the audio ground makes the high-frequency return path and the audio grounding path physically independent, fundamentally eliminating the systemic risk of high-frequency signals coupling to the audio circuit through the shielding layer. Detailed Implementation

[0034] The antenna audio composite coaxial shielded wire based on the intelligent split-and-combination circuit of the present invention includes a coaxial shielded composite wire and an intelligent split-and-combination circuit.

[0035] Coaxial shielded composite conductors consist of an inner conductor, an insulation layer, an outer conductor shielding layer, and an outer sheath. The inner conductor is made of multiple strands of copper wire, exhibiting low DC resistance and high-frequency AC resistance. The insulation layer is extruded from polyethylene or polytetrafluoroethylene (PTFE) around the inner conductor, providing low dielectric constant and dielectric loss. The outer conductor shielding layer is wrapped from the insulation layer with a copper wire braid or aluminum-plastic composite tape, providing both high-frequency signal radiation and electromagnetic shielding. The outer sheath is extruded from polyvinyl chloride (PVC) or thermoplastic elastomer around the outer conductor shielding layer, providing mechanical protection and electrical insulation.

[0036] The characteristic impedance of the coaxial shielded composite cable is set to 50Ω, consistent with the standard output impedance of the walkie-talkie's RF terminal. The length of the coaxial shielded composite cable is set to one-quarter of the wavelength corresponding to the center frequency of the walkie-talkie's operating frequency band. When the walkie-talkie's operating frequency band is 400MHz to 470MHz, the center frequency is approximately 435MHz, corresponding to a wavelength of approximately 0.69m, and one-quarter of the wavelength is approximately 0.17m. Setting the length of the coaxial shielded composite cable to 0.17m or an odd multiple of 0.17m causes the coaxial shielded composite cable to exhibit resonant antenna characteristics near 435MHz.

[0037] The intelligent splitting and combining circuit includes a signal separation module, a high-frequency signal channel, an audio signal channel, an impedance matching unit, and an audio isolation unit.

[0038] The signal separation module includes a high-pass filter unit and a low-pass filter unit, and also incorporates a frequency detection subunit and a switch control subunit. The high-pass filter unit consists of a series capacitor and a parallel inductor, with a cutoff frequency set to 30MHz. The low-pass filter unit consists of a series inductor and a parallel capacitor, with a cutoff frequency set to 20kHz. The walkie-talkie operates in the 400MHz to 470MHz frequency band, and the audio signal frequency ranges from 20Hz to 20kHz. The 30MHz cutoff frequency of the high-pass filter unit is significantly lower than the lower limit of the walkie-talkie's operating frequency band (400MHz), ensuring that high-frequency signals pass through the high-pass filter unit with low loss. The 20kHz cutoff frequency of the low-pass filter unit is higher than the highest audio signal frequency (20kHz), ensuring that the audio signal passes through the low-pass filter unit with low loss. The wide blocking range between the cutoff frequencies of the high-pass and low-pass filter units allows for sufficient separation of the high-frequency signal and the audio signal in the frequency domain.

[0039] The high-frequency signal channel connects the output of the high-pass filter unit to the radio frequency (RF) end of the walkie-talkie. The high-frequency signal channel uses a microstrip line or coaxial cable structure and has a characteristic impedance of 50Ω to ensure low-loss transmission of the high-frequency signal.

[0040] The audio signal channel connects the output of the low-pass filter unit to the walkie-talkie's audio circuitry. The audio signal channel uses twisted-pair or shielded cable, featuring low distributed capacitance to ensure low-distortion audio signal transmission.

[0041] The impedance matching unit is connected between the high-pass filter unit and the high-frequency signal channel. The impedance matching unit uses an L-shaped LC matching network, consisting of a series inductor and a parallel capacitor. The input impedance of the impedance matching unit is set to 50Ω, consistent with the output impedance of the walkie-talkie's RF terminal; the output impedance of the impedance matching unit is set to 50Ω, consistent with the characteristic impedance of the coaxial shielded composite conductor. Through the matching of the impedance matching unit, the reflection loss of the high-frequency signal during transmission is less than -20dB.

[0042] The audio isolation unit connects the low-pass filter unit to the audio signal channel. The audio isolation unit uses ferrite beads, which exhibit an impedance of less than 0.1Ω in the 20Hz to 20kHz audio frequency band and an impedance of more than 500Ω in the 400MHz to 470MHz walkie-talkie operating frequency band. The ferrite beads effectively suppress high-frequency residual signals that may leak into the audio channel, ensuring that the audio signal is not affected by high-frequency interference.

[0043] The second end of the coaxial shielded composite cable is connected to a Type-C connector. The Type-C connector includes pins CC1, CC2, D+, D-, VBUS, and GND. The inner conductor is connected to the D+ pin, and the outer conductor shielding layer is connected to the GND pin. The GND pin is connected to the ground of the walkie-talkie PCB circuit board via an isolation component. In mono mode, the inner conductor is connected to the D+ pin, and the D- pin is left floating. In stereo mode, the coaxial shielded composite cable uses a dual-core coaxial structure, where the first inner conductor is connected to the D+ pin, the second inner conductor is connected to the D- pin, and the outer conductor shielding layer is connected to the GND pin.

[0044] The intelligent switching circuit is integrated onto the Type-C port circuit board of the walkie-talkie. The internal power supply circuit of the walkie-talkie provides operating power to the intelligent switching circuit via a power cord. A decoupling capacitor is connected to the power cord to filter out high-frequency noise.

[0045] The walkie-talkie's radio frequency (RF) ground and audio ground are set up independently, and are electrically isolated from each other by an isolation element. In high-frequency mode, the outer conductor shielding layer is connected to the walkie-talkie's RF ground via a switch, and the return path of the high-frequency signal only passes through the RF ground. In audio mode, the outer conductor shielding layer is connected to the walkie-talkie's audio ground via a switch, and the grounding path of the audio signal only passes through the audio ground. The physical separation of the RF ground and the audio ground makes the high-frequency return path and the audio ground path physically independent.

[0046] The working process of the present invention will be described in detail below.

[0047] In transmit mode, the high-frequency signal generated by the walkie-talkie's RF terminal is transmitted to the impedance matching unit via a high-frequency signal channel. The impedance matching unit converts the impedance of the high-frequency signal from the output impedance of the walkie-talkie's RF terminal to the characteristic impedance of the coaxial shielded composite conductor. After impedance matching, the high-frequency signal enters the high-pass filter unit, which allows high-frequency signals from 400MHz to 470MHz to pass through with an insertion loss of less than 0.5dB, while simultaneously preventing audio signals from entering the high-frequency signal channel. After passing through the high-pass filter unit, the high-frequency signal is transmitted through the outer conductor shielding layer to the far end of the coaxial shielded composite conductor. The coaxial shielded composite conductor is 0.17m long and exhibits quarter-wavelength resonance characteristics at a frequency of 435MHz. The high-frequency current on the outer conductor shielding layer forms a standing wave distribution, with the maximum current occurring at the far end of the coaxial shielded composite conductor, making the coaxial shielded composite conductor act as an antenna radiator radiating electromagnetic waves into space. In high-frequency mode, the outer conductor shielding layer is connected to the walkie-talkie's RF ground via a switching switch, forming the ground reference plane of the antenna radiator.

[0048] In receive mode, spatial electromagnetic waves induce high-frequency signals on the coaxial shielded composite conductor. These induced high-frequency signals are transmitted through the outer conductor shielding layer to a high-pass filter unit. This unit allows high-frequency signals from 400MHz to 470MHz to pass through while preventing external noise signals from entering the audio signal channel. After passing through the high-pass filter unit, the high-frequency signal is transmitted through an impedance matching unit and the high-frequency signal channel to the walkie-talkie's radio frequency (RF) terminal for demodulation. In receive mode, the outer conductor shielding layer is connected to the walkie-talkie's RF ground via a switching switch to ensure the integrity of the received signal while suppressing external electromagnetic interference.

[0049] In audio transmission mode, the audio signal generated by the walkie-talkie's audio circuit is transmitted to the audio isolation unit via the audio signal channel. The ferrite beads in the audio isolation unit present low impedance to audio signals from 20Hz to 20kHz, allowing the audio signal to pass through with a loss of less than 0.1dB. After passing through the audio isolation unit, the audio signal enters the low-pass filter unit, which allows audio signals from 20Hz to 20kHz to pass through while blocking high-frequency signals from 400MHz to 470MHz from entering the audio signal channel. After passing through the low-pass filter unit, the audio signal is transmitted through the inner conductor to the far end of the coaxial shielded composite conductor, driving the headset speaker to produce sound via the D+ pin of the Type-C connector. In audio mode, the outer conductor shielding layer is connected to the walkie-talkie's audio ground via a switch, serving as a grounding loop for the audio signal and providing a low-impedance return path.

[0050] During the above operation, the intelligent splitting and combining circuit performs dynamic routing based on three steps: signal detection, path selection, and shielding layer switching. The signal separation module detects the frequency characteristics of the signal transmitted on the outer conductor shielding layer in real time. When the detected signal frequency is in the range of 400MHz to 470MHz, it is determined to be a high-frequency signal and routed to the high-frequency signal channel. At the same time, the switch is switched to connect the outer conductor shielding layer to the walkie-talkie's RF ground. When the detected signal frequency is in the range of 20Hz to 20kHz, it is determined to be an audio signal and routed to the audio signal channel. At the same time, the switch is switched to connect the outer conductor shielding layer to the walkie-talkie's audio ground. When both high-frequency and audio signals are present, the signal separation module performs path selection in parallel. The high-frequency signal enters the high-frequency signal channel through the high-pass filter unit and is transmitted through the outer conductor shielding layer. The audio signal enters the audio signal channel through the low-pass filter unit and is transmitted through the inner conductor. The two signals are transmitted separately on the coaxial shielded composite conductor without interfering with each other.

[0051] This invention achieves a dual function of antenna and headphone cable by combining the physical structure reuse of the coaxial shielded composite conductor with the frequency-selective separation of the intelligent split-and-combination circuit. The outer conductor shielding layer of the coaxial shielded composite conductor carries high-frequency signals, while the inner conductor carries audio signals. The outer conductor shielding layer is connected to the radio frequency ground and audio ground of the walkie-talkie via a switching switch, serving as the antenna ground reference surface in high-frequency mode and as the audio signal grounding loop in audio mode. The intelligent split-and-combination circuit, through the coordinated operation of a high-pass filter unit, a low-pass filter unit, an impedance matching unit, and an audio isolation unit, achieves frequency-selective separation and impedance matching between the high-frequency and audio signals. The physical structure reuse of the coaxial shielded composite conductor and the frequency-selective separation of the intelligent split-and-combination circuit functionally support each other, together forming a complete signal transmission and radiation system.

[0052] Compared with the prior art, the technical solution of the present invention has the following distinguishing technical features: 1. In the prior art, coaxial shielded wires are only used for single-function transmission, or a single conductor carries two types of signals at the same time. The present invention uses the outer conductor shielding layer of the coaxial shielded wire as a high-frequency signal transmission channel and the inner conductor as an audio signal transmission channel, realizing physical current splitting between the two conductors and naturally reducing signal crosstalk.

[0053] 2. In the prior art, signal separation relies on the frequency division superposition of multiple discrete components on the same conductor. This invention achieves complete physical separation of high-frequency signals and audio signals through physical current splitting and dual isolation of high-pass / low-pass filtering.

[0054] 3. In the prior art, the outer conductor shielding layer of the coaxial cable is always fixed to the ground and is only used as an electromagnetic shielding structure. In this invention, the outer conductor shielding layer is connected to the radio frequency ground and audio ground of the walkie-talkie through a switching switch. The radio frequency ground and audio ground of the walkie-talkie are set independently, realizing the dual-mode multiplexing of the shielding layer function, and transforming the shielding layer from a passive shielding structure into an active functional switching element.

[0055] 4. In the prior art, impedance matching and signal separation are independent of each other. The present invention integrates the impedance matching unit between the signal separation module and the high-frequency signal channel, realizing the integrated design of impedance matching and signal separation.

[0056] 5. Existing technologies use a fixed frequency separation method, where the signal path remains unchanged and the shielding layer is always grounded. This invention employs a dynamic routing method with three steps: signal detection, path selection, and shielding layer switching, which enables real-time coordinated configuration of the signal path and shielding layer functions.

[0057] The physical structure reuse of the coaxial shielded composite wire and the frequency selective separation of the intelligent splitting and combining circuit support each other functionally: physical structure reuse provides the signal transmission basis for frequency selective separation, while frequency selective separation provides signal path protection for physical structure reuse. A single coaxial shielded composite wire replaces the antenna and headphone wires in traditional walkie-talkie wiring, eliminating interference between high-frequency and audio signals and achieving the dual functionality of an antenna and headphone wire.

[0058] The above description is merely a specific embodiment of the present invention, and the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An antenna audio composite coaxial shielded wire based on an intelligent splitting and combining circuit, characterized in that, include: A coaxial shielded composite wire has an inner conductor, an insulating layer covering the outer periphery of the inner conductor, an outer conductor shielding layer covering the outer periphery of the insulating layer, and an outer sheath covering the outer periphery of the outer conductor shielding layer. The outer conductor shielding layer serves as a high-frequency signal transmission and radiation channel for a walkie-talkie antenna, and the inner conductor serves as an audio signal transmission channel for an earphone speaker. The intelligent splitting and combining circuit, connected to the first end of the coaxial shielded composite wire, includes a high-frequency signal channel, an audio signal channel, and a signal separation module, wherein the signal separation module is connected to the high-frequency signal channel and the audio signal channel respectively; The signal separation module detects the frequency characteristics of the signals transmitted in the outer conductor shielding layer in real time, and dynamically routes the high-frequency signal to the high-frequency signal channel and the audio signal to the audio signal channel according to the frequency characteristics, so that the outer conductor shielding layer works as an antenna radiator in the high-frequency signal state and as an audio signal grounding loop in the audio signal state. The outer conductor shielding layer is connected to the radio frequency ground and audio ground of the walkie-talkie via a switching switch, and the radio frequency ground and the audio ground of the walkie-talkie are set independently of each other; in high frequency mode, the switching switch switches the outer conductor shielding layer to be connected to the radio frequency ground of the walkie-talkie, so that the outer conductor shielding layer serves as the antenna ground reference surface; In audio mode, the switch switches the outer conductor shielding layer to be connected to the audio ground of the walkie-talkie, making the outer conductor shielding layer serve as the audio signal grounding loop.

2. The antenna audio composite coaxial shielded wire based on an intelligent splitting and combining circuit according to claim 1, characterized in that, The signal separation module includes a high-pass filter unit and a low-pass filter unit. The input terminal of the high-pass filter unit is connected to the outer conductor shielding layer, and the output terminal is connected to the high-frequency signal channel. The input terminal of the low-pass filter unit is connected to the inner conductor, and the output terminal is connected to the audio signal channel.

3. The antenna audio composite coaxial shielded wire based on an intelligent splitting and combining circuit according to claim 2, characterized in that, The high-pass filter unit consists of a series capacitor and a parallel inductor, and its cutoff frequency is set between the lower limit frequency of the walkie-talkie's operating frequency band and the highest frequency of the audio signal; the low-pass filter unit consists of a series inductor and a parallel capacitor, and its cutoff frequency is set between the highest frequency of the audio signal and the lower limit frequency of the walkie-talkie's operating frequency band.

4. The antenna audio composite coaxial shielded wire based on an intelligent splitting and combining circuit according to claim 1, characterized in that, The intelligent splitting and combining circuit also includes an impedance matching unit, which is connected between the signal separation module and the high-frequency signal channel. The impedance matching unit converts the output impedance of the walkie-talkie's radio frequency terminal into an impedance value that matches the characteristic impedance of the coaxial shielded composite wire.

5. The antenna audio composite coaxial shielded wire based on an intelligent splitting and combining circuit according to claim 4, characterized in that, The impedance matching unit is a π-type resistance attenuation network or an L-type LC matching network. The input impedance of the impedance matching unit is equal to the output impedance of the radio frequency terminal of the walkie-talkie, and the output impedance of the impedance matching unit is equal to the characteristic impedance of the coaxial shielded composite wire.

6. The antenna audio composite coaxial shielded wire based on an intelligent splitting and combining circuit according to claim 1, characterized in that, The intelligent splitting and combining circuit also includes an audio isolation unit, which is connected between the signal separation module and the audio signal channel. The audio isolation unit suppresses high-frequency residual components in the audio signal channel.

7. The antenna audio composite coaxial shielded wire based on an intelligent splitting and combining circuit according to claim 6, characterized in that, The audio isolation unit is a common-mode choke or a ferrite bead. The audio isolation unit presents low impedance in the audio frequency band and high impedance in the walkie-talkie operating frequency band.

8. The antenna audio composite coaxial shielded wire based on an intelligent splitting and combining circuit according to claim 1, characterized in that, The second end of the coaxial shielded composite conductor is connected to a Type-C connector, which includes a CC1 pin, a CC2 pin, a D+ pin, a D- pin, a VBUS pin, and a GND pin. The inner conductor is connected to at least one of the D+ pin and the D- pin, and the outer conductor shielding layer is connected to the GND pin. The GND pin is connected to the ground of the walkie-talkie PCB circuit board through an isolation element.

9. The antenna audio composite coaxial shielded wire based on an intelligent splitting and combining circuit according to claim 1, characterized in that, The length of the coaxial shielded composite wire is set to be an integer multiple of one-quarter of the wavelength corresponding to the center frequency of the walkie-talkie's operating frequency band, so that the coaxial shielded composite wire exhibits resonant antenna characteristics within the walkie-talkie's operating frequency band.

10. The antenna audio composite coaxial shielded wire based on an intelligent splitting and combining circuit according to claim 1, characterized in that, The intelligent split-connect circuit is integrated into the Type-C port circuit board of the walkie-talkie or the external adapter, and the power supply of the intelligent split-connect circuit is provided by the internal power supply circuit of the walkie-talkie.