A method for directional sound propagation from a walkie-talkie speaker

Abstract

This invention relates to the field of wireless communication technology, and in particular to a method for directional sound propagation in a walkie-talkie speaker. This invention achieves directional sound propagation, reduces noise pollution, and enhances the security of the walkie-talkie because the sound does not scatter in all directions. Furthermore, by employing ultrasonic carrier modulation technology, namely audio and carrier comparator synthesis and dynamic modulation depth control, directional sound propagation is achieved on the basis of the original hardware of a regular walkie-talkie without the need to reconstruct the entire device. This breaks through the limitation of traditional directional speakers requiring dedicated hardware, presents a novel technical approach, significantly reduces the implementation cost of directional propagation, and facilitates the large-scale promotion and application of regular walkie-talkies.

Description

Technical Field

[0001] This invention relates to the field of wireless communication technology, and in particular to a method for directional sound propagation from a walkie-talkie speaker. Background Technology

[0002] A walkie-talkie is a two-way communication device based on radio technology, used to achieve real-time voice communication. It can make calls without any network support and without incurring call charges. Walkie-talkies are widely used in scenarios that require fast and direct communication, such as construction site dispatching, logistics management, security patrols, and outdoor sports. The speaker is one of the core components of a walkie-talkie, used to convert the received radio signals into sound for the user to hear. The speaker directly determines the sound quality and call clarity of the walkie-talkie, and its performance is especially important in noisy environments.

[0003] Existing walkie-talkies, when in use, have speakers that broadcast sound in all directions, causing noise pollution. Furthermore, when users engage in private conversations, the sound can easily spread in all directions, compromising the confidentiality of the walkie-talkie. While existing walkie-talkies, such as the one with publication number CN205883219U, disclose a directional sound transmission method, they require specialized hardware and a complete redesign of the walkie-talkie, limiting their widespread use on ordinary walkie-talkies. Summary of the Invention

[0004] Therefore, in order to overcome the above-mentioned shortcomings, the present invention provides a method for directional sound propagation of a walkie-talkie speaker to solve the above-mentioned technical problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a method for directional sound propagation from a walkie-talkie speaker, comprising the following steps:

[0006] S1, Audio Modulation: Input a 20Hz-20kHz audio signal, and synthesize the input audio signal and the carrier signal through a comparator. When the instantaneous audio voltage is greater than the carrier voltage, the output is high level; otherwise, the output is low level.

[0007] S2, Carrier Modulation: Configure the STM32 timer to PWM mode to generate a reference carrier signal with a carrier frequency range of 38-42kHz. Adjust the frequency ±2kHz in real time according to the ambient temperature and humidity to compensate for air attenuation.

[0008] S3, Directional Emission: A piezoelectric ceramic unit with a resonant frequency of 40kHz±1% is used as the core transducer, and a narrow sound beam is formed through the acoustic structure of the reflector for directional propagation;

[0009] S4. Air demodulation: Ultrasonic waves are automatically demodulated during propagation in the air due to nonlinear effects, restoring audible sound waves in the target area, while the sound pressure level outside the area is attenuated to the point where audible sound waves cannot be clearly perceived.

[0010] By following the steps above, the sound wave propagation angle can be controlled within ±15° and the propagation distance can be ≤20 meters.

[0011] Preferably, the audio modulation step further includes modulation depth control, which is to dynamically adjust the audio gain so that the modulation depth is maintained between 30% and 100%.

[0012] Preferably, the carrier modulation step selects a carrier frequency of 38-42kHz to avoid common environmental noise interference.

[0013] Preferably, the core transducer employs a piezoelectric ceramic unit that supports high-power ultrasonic emission.

[0014] Preferably, the reflector used in the directional emission step is designed to form a narrow sound beam with an angle within ±15° to achieve directional propagation.

[0015] Preferably, the air demodulation step relies on the nonlinear effect that occurs when ultrasound propagates in the air, which enables the ultrasound to recover the original audio signal within a specific receiving area with a propagation distance ≤ 20 meters.

[0016] The beneficial effects of this invention are:

[0017] 1. This invention achieves directional sound propagation, reducing noise pollution. Furthermore, since the sound does not scatter in all directions, the security of the walkie-talkie is enhanced. Moreover, through ultrasonic carrier modulation technology, namely audio and carrier comparator synthesis and dynamic modulation depth control, directional sound propagation is achieved on the basis of the original hardware of ordinary walkie-talkies without the need to reconstruct the entire device. This breaks through the limitation of traditional directional speakers requiring dedicated hardware. The novel technical approach significantly reduces the implementation cost of directional propagation function, making it easy for ordinary walkie-talkies to be widely promoted and applied.

[0018] 2. This invention achieves automatic demodulation by utilizing the nonlinear effect of ultrasonic waves propagating in the air. It can restore audible sound waves without the need for additional equipment at the receiving end, simplifying the implementation process of directional propagation. Compared with traditional directional technologies that require cooperation between the transmitting and receiving ends, it is more practical. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the workflow of the present invention. Detailed Implementation

[0020] To further explain the technical solution of the present invention, a detailed description is provided below through specific embodiments.

[0021] like Figure 1 As shown, the present invention provides a method for directional sound propagation from a walkie-talkie speaker, comprising the following steps:

[0022] S1. Audio Modulation: The original walkie-talkie inputs a 20Hz-20kHz audio signal. After preprocessing by the original audio amplifier circuit of the walkie-talkie, the input audio signal and the carrier signal are combined by a comparator. When the instantaneous audio voltage is greater than the carrier voltage, the output is high level, and vice versa.

[0023] S2, Carrier Modulation: Configure the timer of the STM32 chip in the ordinary walkie-talkie, adjust the timer to PWM mode to generate a reference carrier signal, and the carrier frequency range is 38-42kHz to avoid common environmental noise interference. The ambient temperature and humidity are collected by the temperature and humidity sensor in the walkie-talkie, and the frequency is finely adjusted by ±2kHz in real time according to the ambient temperature and humidity to compensate for air attenuation.

[0024] S3, Directional Transmission: A piezoelectric ceramic unit with a resonant frequency of 40kHz±1% is used as the core transducer. The transducer is driven by the power amplifier module of the original walkie-talkie, and a narrow sound beam is formed through the acoustic structure of the reflector for directional propagation.

[0025] S4. Air demodulation: Ultrasonic waves are automatically demodulated during propagation in the air due to nonlinear effects, restoring audible sound waves in the target area, while the sound pressure level outside the area is attenuated to the point where audible sound waves cannot be clearly perceived.

[0026] Through the above steps, the sound wave propagation angle is controlled within ±15° and the propagation distance is ≤20 meters;

[0027] The audio modulation step also includes modulation depth control, which is to dynamically adjust the audio gain. This ensures that the audio signal can fully modulate the carrier under different input intensities, thereby improving the clarity and fidelity of the sound. It keeps the modulation depth between 30% and 100%, thereby avoiding distortion and ensuring that the modulated signal is within a reasonable range.

[0028] The core transducer uses a piezoelectric ceramic unit that supports high-power ultrasonic emission, which facilitates efficient energy conversion and precise frequency control.

[0029] The reflector used in the directional emission step is designed to form a narrow sound beam with an angle within ±15° to achieve directional propagation.

[0030] The air demodulation step relies on the nonlinear effect that occurs when ultrasound propagates in the air. This nonlinear effect enables the ultrasound to recover the original audio signal within a specific receiving area with a propagation distance of ≤20 meters, resulting in stronger directional propagation.

[0031] Specifically, in summary, by adopting the above-mentioned solution of the present invention, the directional sound propagation function can be achieved by simply replacing the speaker with a piezoelectric ceramic unit and adding a reflector to the adapter shell, using the core hardware of a common walkie-talkie, such as the STM32 main control, audio interface, power amplifier module, etc., and adding a reflector to the adapter shell. The piezoelectric ceramic unit used has a power of 1W-5W. Combined with ultrasonic carrier modulation technology (audio and carrier comparator synthesis, dynamic modulation depth control, etc.), the entire machine does not need to be redesigned, reducing the cost required for the walkie-talkie to achieve directional sound propagation, and thus upgrading the walkie-talkie's functionality.

[0032] Furthermore, by combining a piezoelectric ceramic transducer with a resonant frequency of 40kHz±1% with a reflector acoustic structure, the sound wave propagation angle is strictly controlled within ±15°. At the same time, the carrier frequency is dynamically compensated by ambient temperature and humidity to ensure clear demodulation within a 20-meter directional area, while the sound pressure level outside the area is attenuated to an imperceptible level, meeting the actual needs of short-range directional communication. In addition, when ultrasound propagates in the air, it automatically demodulates due to nonlinear effects, and can reproduce audible sound waves in the target area without additional equipment at the receiving end, simplifying the implementation process of directional propagation. The sound pressure level attenuation outside the area can reach 90%. By realizing directional sound propagation, noise pollution is reduced, solving the privacy leakage and environmental interference problems caused by sound diffusion of traditional walkie-talkies, and making ordinary walkie-talkies more secure.

[0033] This invention provides a method for directional sound propagation in walkie-talkies, achieving directional sound propagation, reducing noise pollution, and enhancing the security of the walkie-talkie because the sound does not scatter in all directions. Furthermore, by employing ultrasonic carrier modulation technology, including audio and carrier comparator synthesis and dynamic modulation depth control, directional sound propagation is achieved on the basis of the original hardware of ordinary walkie-talkies without the need to reconstruct the entire device. This breaks through the limitation of traditional directional speakers requiring dedicated hardware, presents a novel technical approach, significantly reduces the implementation cost of directional propagation, and facilitates the large-scale promotion and application of ordinary walkie-talkies.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for directional sound propagation from a walkie-talkie speaker, characterized in that, Includes the following steps: S1, Audio Modulation: Input a 20Hz-20kHz audio signal, and synthesize the input audio signal and the carrier signal through a comparator. When the instantaneous audio voltage is greater than the carrier voltage, the output is high level; otherwise, the output is low level. S2, Carrier Modulation: Configure the STM32 timer to PWM mode to generate a reference carrier signal with a carrier frequency range of 38-42kHz. Adjust the frequency ±2kHz in real time according to the ambient temperature and humidity to compensate for air attenuation. S3, Directional Emission: A piezoelectric ceramic unit with a resonant frequency of 40kHz±1% is used as the core transducer, and a narrow sound beam is formed through the acoustic structure of the reflector for directional propagation; S4. Air demodulation: Ultrasonic waves are automatically demodulated during propagation in the air due to nonlinear effects, restoring audible sound waves in the target area, while the sound pressure level outside the area is attenuated to the point where audible sound waves cannot be clearly perceived. Through the above steps, the sound wave propagation angle is controlled within ±15° and the propagation distance is ≤20 meters; The audio modulation step also includes modulation depth control, which is to dynamically adjust the audio gain so that the modulation depth is maintained between 30% and 100%.

2. The method for directional sound propagation of a walkie-talkie speaker according to claim 1, characterized in that: The carrier modulation step selects a carrier frequency of 38-42kHz.

3. The method for directional sound propagation of a walkie-talkie speaker according to claim 1, characterized in that: The reflector used in the directional emission step is designed to form a narrow sound beam with an angle within ±15° to achieve directional propagation.

4. The method for directional sound propagation of a walkie-talkie speaker according to claim 1, characterized in that: The air demodulation step relies on the nonlinear effect that occurs when ultrasound propagates in the air, which enables the ultrasound to recover the original audio signal within a specific receiving area with a propagation distance of ≤20 meters.

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