Outdoor high-definition screen equipment, audio playing method, terminal and storage medium

Abstract

The invention belongs to the technical field of audio and video equipment, and particularly relates to outdoor high-definition screen equipment, an audio playing method, a terminal and a storage medium, the outdoor high-definition screen equipment comprises an audio adjusting circuit which is in communication connection with a microcontroller, and the audio adjusting circuit is used for performing frequency modulation on audio matched with a video played on a high-definition screen body according to a control signal of the microcontroller; and the audio frequency after frequency modulation is sent to a radio terminal of the audience. By introducing the audio adjusting circuit and the frequency modulation emission technology, the problem of outdoor high-definition screen equipment in the aspect of sound transmission is effectively solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of audio and video equipment, and specifically relates to an outdoor high-definition screen device, an audio playback method, a terminal and a storage medium. Background Art

[0002] Existing technologies for outdoor high-definition screens face numerous challenges in sound transmission. Outdoor high-definition LED screens are widely used throughout cities to publicize and broadcast important information. However, these screens are often installed outdoors in locations such as high-rise buildings, making sound transmission a challenge for viewers hundreds of meters away.

[0003] Traditionally, high-definition screens rely on standard speakers for sound reproduction. However, speakers are limited in power and transmission distance, preventing distant viewers from clearly hearing the information and instead viewing the silent images. While using high-power speakers can increase the volume, this often causes significant noise disturbance to nearby residents and violates urban management regulations.

[0004] The industry has made numerous attempts to address the issue of sound transmission. However, traditional sound transmission methods, such as increasing speaker power or using wired amplification equipment, have significant limitations. Increasing speaker power can not only exacerbate noise pollution, but also make it difficult to effectively reach all audiences in complex environments. Wired amplification equipment, however, is limited by wiring, making it inconvenient to deploy over large outdoor areas and detracting from the aesthetics of a city.

[0005] Therefore, there is an urgent need for a new type of sound transmission method that can ensure that distant audiences can hear the sound clearly without causing noise interference to nearby residents. Summary of the Invention

[0006] In view of the defects in the prior art that the existing outdoor high-definition screen equipment relies on speakers to play sound, and increasing the power of the speakers not only causes noise pollution but also makes it difficult for the sound to effectively cover all audiences. In addition, the wired sound amplification equipment is limited by wiring and is not convenient for large-scale outdoor deployment, the present invention provides an outdoor high-definition screen device, an audio playback method, a terminal and a storage medium to solve the above technical problems.

[0007] In a first aspect, the present invention provides an outdoor high-definition screen device, comprising a high-definition screen body and a microcontroller connected to the high-definition screen for communication, and also comprising an audio adjustment circuit connected to the microcontroller for communication, the audio adjustment circuit being used to frequency-modulate the audio matching the video played on the high-definition screen body according to a control signal of the microcontroller, and to send the frequency-modulated audio to the audience's radio terminal.

[0008] A further improvement of the present technical solution is that the audio adjustment circuit includes an audio amplification circuit, an FM transmission circuit and a power supply circuit for powering the entire audio adjustment circuit; the input end of the audio amplification circuit is connected to an external audio signal source device, the output end of the audio amplification circuit is connected to the input end of the FM transmission circuit, and the output end of the FM transmission circuit is wirelessly connected to the audience's radio terminal.

[0009] A further improvement of the technical solution is that the audio amplifier circuit includes a left channel interface LINE-L, a right channel interface LINE-R, a capacitor C1, a resistor R1, a capacitor C2, a resistor R2, a resistor R3, an audio amplifier U1, a capacitor C3, a variable resistor R4, a capacitor C4, and a resistor R5; The input end of the left channel interface LINE-L and the input end of the right channel interface LINE-R are both connected to an external audio signal source device, the output end of the right channel interface LINE-R is connected to the first end of the resistor R1 through the capacitor C1, the output end of the left channel interface LINE-L is connected to the first end of the resistor R2 through the capacitor C2, the second end of the resistor R1 and the second end of the resistor R2 are both connected to the inverting input end of the audio amplifier U1 and the first end of the resistor R3, the non-inverting input end of the audio amplifier U1 is connected to the FM transmitting circuit, the output end of the audio amplifier U1 is connected to the second end of the resistor R3 and the first end of the capacitor C3, the second end of the capacitor C3 is connected to the first end of the variable resistor R4, the second end of the variable resistor R4 is grounded, the active end of the variable resistor R4 is connected to the first end of the resistor R5 through the capacitor C4, and the second end of the resistor R5 is connected to the FM transmitting circuit.

[0010] A further improvement of the technical solution is that the FM transmitting circuit includes a variable resistor R6, an amplifier U2, a resistor R7, a capacitor C5, a constant current source I1, a diode D1, a resistor R8, a capacitor C6, an amplifier U3, a resistor R9, a variable resistor R10, a resistor R11, a varactor diode D2, a capacitor C7, a variable capacitor C8, an inductor L1, a capacitor C9, a resistor R12, a field effect transistor Q1, a capacitor C10, a capacitor C11, a magnetic core inductor L2, a capacitor C12, a resistor R13, a transistor Q2, a capacitor C13, a coupling transformer B1, an antenna ANT1 and a capacitor C14; The inverting input of the amplifier U2 is connected to the active end of the variable resistor R6, the non-inverting input of the amplifier U2 is connected to the non-inverting input of the audio amplifier U1, the first end of the variable resistor R6, the non-inverting input of the amplifier U3, the first end of the resistor R7, the first end of the capacitor C5, the first end of the constant current source I1 and the positive electrode of the diode D1, the output of the amplifier U2 is connected to the second end of the resistor R8 and the first end of the capacitor C6, the second end of the capacitor C6 is connected to the second end of the resistor R7, the second end of the capacitor C5, the second end of the constant current source I1 and the negative electrode of the diode D1; the inverting input of the amplifier U3 is connected to the second end of the resistor R5, the output of the amplifier U3 is connected to the first end of the resistor R9, the first end of the resistor R10 and the first end of the resistor R11, the second end of the resistor R9 is connected to the inverting input of the amplifier U3, and the second end of the resistor R10 is connected to the second end of the variable resistor R6; The second end of the resistor R11 is connected to the cathode of the varactor diode D2 and the first end of the capacitor C7, the second end of the capacitor C7 is connected to the first end of the variable capacitor, the first end of the inductor L1 and the first end of the capacitor C9, the second end of the capacitor C9 is connected to the first end of the resistor R12, the first end of the capacitor C10 and the gate of the field effect transistor Q1, the second end of the capacitor C10 is connected to the first end of the capacitor C11, the first end of the magnetic core inductor L2, the source of the field effect transistor Q1 and the first end of the capacitor C12, the second end of the capacitor C12 is connected to the first end of the resistor R13 and the base of the transistor Q2, the anode of the varactor diode D2, the second end of the variable capacitor C8, the second end of the inductor L1, the second end of the resistor R12, the second end of the capacitor C11, the The second end, the second end of the resistor R13, and the emitter of the transistor Q2 are all grounded. The collector of the transistor Q2 is connected to the first end of the capacitor C13 and the first end of the primary coil of the coupling transformer B1. The second end of the capacitor C13 is connected to the second end of the primary coil of the coupling transformer B1. The drain of the field effect transistor Q1 and the active end of the primary coil of the coupling transformer B1 are both connected to the power supply circuit and grounded through the capacitor C14. The first end of the secondary coil of the coupling transformer B1 is connected to the input end of the antenna ANT. The second end of the secondary coil of the coupling transformer B1 and the ground end of the antenna ANT are both grounded. The output end of the antenna ANT is wirelessly connected to the viewer's radio terminal. The constant current source I1, the varactor diode D2, and the variable capacitor C8 are all communicatively connected to the microcontroller.

[0011] A further improvement of the technical solution is that the power supply circuit includes a capacitor C15, a resistor R14, a capacitor C16, a resistor R15, a capacitor C17, a three-hole power interface P1 and a battery BATT; The first end of the three-hole power interface P1, the first end of the capacitor C15, the first end of the resistor R14, the first end of the capacitor C16 and the drain of the field effect transistor Q1 are all connected to the external power supply VCC, the second end of the capacitor C15 and the second end of the capacitor C16 are both grounded, the second end of the resistor R14 is connected to the first end of the resistor R15 and the first end of the capacitor C17, the second end of the three-hole power interface P1 is connected to the positive pole of the battery BATT, and the third end of the three-hole power interface P1, the negative pole of the battery BATT, the second end of the resistor R15 and the second end of the capacitor C17 are all grounded.

[0012] In a second aspect, the present invention provides an audio playback method applicable to any of the above-mentioned outdoor high-definition screen devices, comprising: The environment of the outdoor high-definition screen device is detected by several spectrum analyzers arranged around the outdoor high-definition screen device, and the detected spectrum data is sent to the microcontroller; The microcontroller analyzes the received spectrum data, finds the idle frequency points and marks them; The microcontroller modulates the playback frequency of the outdoor high-definition screen device to the marked idle frequency through the audio adjustment circuit according to the pre-stored frequency switching strategy; The microcontroller controls the outdoor high-definition screen device to display the marked idle frequency points at a preset position, and the audience sets the receiving frequency point of the radio terminal to the idle frequency point displayed in the outdoor high-definition screen device and then answers the call.

[0013] A further improvement of this technical solution is that the pre-stored frequency switching strategy includes: The microcontroller selects a frequency band containing three or more consecutive idle frequency points from the marked idle frequency points; The microcontroller controls amplifier U2 to perform gain compensation on the audio signal; The microcontroller calculates the signal strength mutation rate according to the signal strength fed back by the spectrum analyzer, and determines whether the calculated signal strength mutation rate is greater than or equal to a preset mutation rate threshold; If so, the microcontroller controls the constant current source I1 to provide a reverse bias current to the varactor diode D2 and sets the capacitance value of the initial variable capacitor C8 to lock the target frequency band from the screened frequency bands; When the microcontroller detects interference in the same frequency band, it selects the optimal frequency point for impedance matching and dynamically adjusts the capacitance value of the variable capacitor C8.

[0014] Further improvements to this technical solution include estimating the farthest audience distance d of the outdoor high-definition screen device based on a WIFI probe connected to the spectrum analyzer, and dynamically controlling the output power of the audio adjustment circuit based on the estimated farthest audience distance d.

[0015] In a third aspect, the present invention provides a terminal, comprising: processor, memory, wherein The memory is used to store computer programs, The processor is used to call and run the computer program from the memory, so that the terminal executes the above-mentioned terminal method.

[0016] In a fourth aspect, the present invention provides a computer storage medium, wherein the computer-readable storage medium stores instructions, which, when executed on a computer, enable the computer to execute the methods described in the above aspects.

[0017] The beneficial effects of the present invention are: This invention effectively solves the sound transmission challenges of outdoor high-definition screens by introducing an audio conditioning circuit and FM transmission technology. Traditional high-definition screens rely on conventional speakers for sound playback, which have limited power and transmission distance, preventing distant viewers from clearly hearing the information. However, this invention uses an audio conditioning circuit to FM the audio and wirelessly transmits the modulated audio to the viewer's radio terminal, thus enabling long-distance sound transmission. This improvement not only increases the sound transmission coverage but also ensures sound clarity.

[0018] The present invention also achieves intelligent selection and switching of playback frequencies through the collaboration of a microcontroller and a spectrum analyzer. Based on spectrum data detected by the spectrum analyzer, the microcontroller identifies and marks idle frequencies. Then, based on a pre-stored frequency switching strategy, the playback frequency is modulated to an idle frequency. This function not only improves spectrum resource utilization but also avoids interference with other radio equipment.

[0019] This invention also provides a function for dynamically adjusting the output power of the audio conditioning circuit based on the maximum audience distance. By using a Wi-Fi probe connected to a spectrum analyzer to estimate the maximum audience distance for outdoor HD screens, the microcontroller dynamically adjusts the output power of the audio conditioning circuit based on this distance, thereby ensuring sound coverage while avoiding unnecessary energy waste and noise pollution.

[0020] In addition, the present invention has a reliable design principle, a simple structure and a very broad application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0022] Figure 1 This is a schematic block diagram of an outdoor high-definition screen device.

[0023] Figure 2 This is the schematic diagram of the audio amplifier circuit.

[0024] Figure 3 This is the schematic diagram of the FM transmitter circuit.

[0025] Figure 4 This is the schematic diagram of the power supply circuit.

[0026] Figure 5 A schematic flow chart of a method according to an embodiment of the present invention.

[0027] Figure 6 A schematic diagram of the structure of a terminal provided by an embodiment of the present invention.

[0028] 110 is the high-definition screen body, 120 is the microcontroller, 130 is the audio adjustment circuit, 131 is the audio amplification circuit, 132 is the FM transmission circuit, and 133 is the power supply circuit. DETAILED DESCRIPTION

[0029] In order to make the purpose, features, and advantages of the present invention more obvious and easy to understand, the technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings in the specific embodiments. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0031] The key terms appearing in the present invention are explained below.

[0032] LED, the full name of which is Light-Emitting Diode, means light-emitting diode in Chinese. It is a semiconductor device that converts electrical energy into light and is used for indicator lights, display screens, etc.

[0033] HDMI, the full name of which is High-Definition Multimedia Interface in English, means High-Definition Multimedia Interface in Chinese. It supports full digital transmission of audio and video and is used to connect monitors, TVs and other devices.

[0034] SPI, the full name of which is Serial Peripheral Interface, is a high-speed synchronous serial bus used for communication between microcontrollers and peripherals such as sensors and memory.

[0035] ADC, the full name of which is Analog-to-Digital Converter, converts analog signals (such as audio and sensor data) into digital signals for processing by microcontrollers.

[0036] FM, which stands for Frequency Modulation in English, means frequency modulation in Chinese. It transmits information by changing the carrier frequency and is used in scenarios such as broadcasting and wireless microphones.

[0037] WIFI, the full name of which is Wireless Fidelity (unofficial abbreviation, common name in the industry), means wireless local area network technology in Chinese. It is based on the IEEE 802.11 standard and supports devices to connect to the wireless network through the 2.4GHz / 5GHz frequency band.

[0038] RSSI, the full name of which is Received Signal Strength Indicator, quantifies the wireless signal power (in dBm) and is used to evaluate signal quality and interference.

[0039] MTBF, short for Mean Time Between Failures, is an indicator for measuring equipment reliability and represents the average operating time between two failures.

[0040] like Figure 1As shown, the present invention provides an outdoor high-definition screen device, including a high-definition screen body and a microcontroller connected to the high-definition screen, and also including an audio adjustment circuit connected to the microcontroller. The audio adjustment circuit is used to frequency-modulate the audio that matches the video played on the high-definition screen body according to the control signal of the microcontroller, and send the frequency-modulated audio to the audience's radio terminal. Among them, the high-definition screen body adopts a PH5 outdoor LED high-definition screen body with a brightness of ≥5000cd / m², ensuring clear display even in a strong light environment, thereby improving the audience's visual experience; supporting HDR10+ decoding, and receiving video signals through an HDMI interface. The back of the screen is integrated with a heat-dissipating aluminum substrate to ensure stable operation in an environment of -30°C to 70°C, broadening the scope of use of the equipment and enhancing the reliability of the equipment. The microcontroller uses an STM32F407VGT6 chip with dual SPI channels, running at a main frequency of 168MHz. It connects to the HD screen driver board (MAX7219) via SPI1, while SPI2 controls the audio conditioning circuit. The audio is frequency-modulated according to the microcontroller's control signals and transmitted to the audience's radio terminal, enabling wireless sound transmission and addressing the power and transmission distance limitations of traditional speakers. A built-in 12-bit ADC module (sampling rate 1MHz) collects ambient noise signals in real time, providing accurate noise data to the audio conditioning circuit and optimizing audio transmission. The radio terminal can be a mobile phone or a digitally tuned FM headset supporting the 76 to 88MHz band (such as the Sony MDR-IF240RK), with a sensitivity of ≤1μV and a signal-to-noise ratio of ≥70dB. Audiences can listen using their mobile phone or standard FM headphones without purchasing additional equipment, enhancing the device's convenience and practicality.

[0041] Specifically, the audio adjustment circuit includes an audio amplification circuit, an FM transmission circuit and a power supply circuit for powering the entire audio adjustment circuit; the input end of the audio amplification circuit is connected to an external audio signal source device, the output end of the audio amplification circuit is connected to the input end of the FM transmission circuit, and the output end of the FM transmission circuit is wirelessly connected to the audience's radio terminal.

[0042] like Figure 2As shown, the audio amplifier circuit includes a left channel interface LINE-L, a right channel interface LINE-R, a capacitor C1, a resistor R1, a capacitor C2, a resistor R2, a resistor R3, an audio amplifier U1, a capacitor C3, a variable resistor R4, a capacitor C4, and a resistor R5; the input end of the left channel interface LINE-L and the input end of the right channel interface LINE-R are both connected to an external audio signal source device, the output end of the right channel interface LINE-R is connected to the first end of the resistor R1 through the capacitor C1, the output end of the left channel interface LINE-L is connected to the first end of the resistor R2 through the capacitor C2, the second end of the resistor R1 and the second end of the resistor R2 are both connected to the inverting input end of the audio amplifier U1 and the first end of the resistor R3, the non-inverting input end of the audio amplifier U1 is connected to the FM transmitting circuit, the output end of the audio amplifier U1 is connected to the second end of the resistor R3 and the first end of the capacitor C3, the second end of the capacitor C3 is connected to the first end of the variable resistor R4, the second end of the variable resistor R4 is grounded, the active end of the variable resistor R4 is connected to the first end of the resistor R5 through the capacitor C4, and the second end of the resistor R5 is connected to the FM transmitting circuit.

[0043] Among them, capacitors C1 and C2 are used to filter out the DC component in the audio signal and retain the AC audio signal from 20Hz to 20kHz, ensuring that only the AC audio signal from 20Hz to 20kHz is retained to enter the subsequent circuit, thereby improving the purity of the audio signal; resistors R1 and R2 can limit the input current to prevent the audio amplifier input from overload; the audio amplifier U1 receives the LINE-L / R signal and forms an inverting amplifier through resistors R1 / R2 and feedback resistor R3. This design not only amplifies the audio signal, but also improves the stability and linearity of the amplifier through the feedback mechanism; coupling through capacitor C3 , filtering out high-frequency noise (ESR < 0.1Ω), further ensuring the clarity and purity of the audio signal; changing the position of the active end of the variable resistor R4 to adjust the output signal amplitude meets the requirements of different application scenarios for audio output amplitude; capacitor C4 and resistor R5 form an RC low-pass filter (cut-off frequency 159kHz), which effectively filters out high-frequency interference and ensures smooth output of the audio signal; resistor R5 is connected in series at the output end of the audio amplifier U1, achieving a good match with the input impedance of the FM transmitter circuit (standard 50Ω), reducing signal reflection, making the reflection loss <-20dB, and improving signal transmission efficiency.

[0044] like Figure 3As shown, the FM transmitting circuit includes a variable resistor R6, an amplifier U2, a resistor R7, a capacitor C5, a constant current source I1, a diode D1, a resistor R8, a capacitor C6, an amplifier U3, a resistor R9, a variable resistor R10, a resistor R11, a varactor diode D2, a capacitor C7, a variable capacitor C8, an inductor L1, a capacitor C9, a resistor R12, a field effect transistor Q1, a capacitor C10, a capacitor C11, a magnetic core inductor L2, a capacitor C12, a resistor R13, a transistor Q2, a capacitor C13, a coupling transformer B1, an antenna ANT1 and a capacitor C14; the inverting input terminal of the amplifier U2 is connected to the active end of the variable resistor R6, and the non-inverting input terminal of the amplifier U2 is connected to the non-inverting input terminal of the audio amplifier U1 and the first inverting terminal of the variable resistor R6. The first terminal of the amplifier U3 is connected to the first terminal of the resistor R7, the first terminal of the capacitor C5, the first terminal of the constant current source I1 and the positive electrode of the diode D1. The output terminal of the amplifier U2 is connected to the second terminal of the resistor R8 and the first terminal of the capacitor C6. The second terminal of the capacitor C6 is connected to the second terminal of the resistor R7, the second terminal of the capacitor C5, the second terminal of the constant current source I1 and the negative electrode of the diode D1. The inverting input terminal of the amplifier U3 is connected to the second terminal of the resistor R5. The output terminal of the amplifier U3 is connected to the first terminal of the resistor R9, the first terminal of the resistor R10 and the first terminal of the resistor R11. The second terminal of the resistor R9 is connected to the inverting input terminal of the amplifier U3. The second terminal of the resistor R10 is connected to the second terminal of the variable resistor R6. The second terminal of the resistor R11 connected to the cathode of the varactor diode D2 and the first end of the capacitor C7, the second end of the capacitor C7 is connected to the first end of the variable capacitor, the first end of the inductor L1 and the first end of the capacitor C9, the second end of the capacitor C9 is connected to the first end of the resistor R12, the first end of the capacitor C10 and the gate of the field effect transistor Q1, the second end of the capacitor C10 is connected to the first end of the capacitor C11, the first end of the magnetic core inductor L2, the source of the field effect transistor Q1 and the first end of the capacitor C12, the second end of the capacitor C12 is connected to the first end of the resistor R13 and the base of the transistor Q2, the anode of the varactor diode D2, the second end of the variable capacitor C8, the second end of the inductor L1, the second end of the resistor R12, the second end of the capacitor C11, the second end of the magnetic core inductor L2, The second end of resistor R13 and the emitter of transistor Q2 are both grounded. The collector of transistor Q2 is connected to the first end of capacitor C13 and the first end of the primary coil of coupling transformer B1. The second end of capacitor C13 is connected to the second end of the primary coil of coupling transformer B1. The drain of field-effect transistor Q1 and the active end of the primary coil of coupling transformer B1 are both connected to the power supply circuit and grounded through capacitor C14. The first end of the secondary coil of coupling transformer B1 is connected to the input end of antenna ANT. The second end of the secondary coil of coupling transformer B1 and the ground end of antenna ANT are both grounded. The output end of antenna ANT is wirelessly connected to the viewer's radio terminal. Constant current source I1, varactor diode D2, and variable capacitor C8 are all communicatively connected to the microcontroller.

[0045] Among them, field-effect transistor Q1 (pre-driver stage) operates in Class A mode. The gate receives the modulated signal through capacitor C9. The source load is a parallel resonant circuit of magnetic core inductor L2 and capacitor C11, which helps filter out unwanted high-frequency components and improve signal purity. Transistor Q2 (power amplifier stage) is configured as a Class C amplifier with a base bias voltage of 0.7V. The collector achieves impedance transformation (50Ω→200Ω) through coupling transformer B1. The output power is continuously adjustable (10-100mW), meeting the requirements of different power transmissions, while ensuring impedance matching with antenna ANT and improving signal transmission efficiency. In addition, the circuit introduces variable resistor R6, varactor diode D2, and variable capacitor C8. These components are all connected to the microcontroller, enabling precise control and flexible adjustment of the transmission frequency to meet the requirements of transmission in different frequency bands.

[0046] like Figure 4 As shown, the power supply circuit includes a capacitor C15, a resistor R14, a capacitor C16, a resistor R15, a capacitor C17, a three-hole power interface P1 and a battery BATT; the first end of the three-hole power interface P1, the first end of the capacitor C15, the first end of the resistor R14, the first end of the capacitor C16 and the drain of the field effect transistor Q1 are all connected to the external power supply VCC, the second end of the capacitor C15 and the second end of the capacitor C16 are both grounded, the second end of the resistor R14 is connected to the first end of the resistor R15 and the first end of the capacitor C17, the second end of the three-hole power interface P1 is connected to the positive electrode of the battery BATT, and the third end of the three-hole power interface P1, the negative electrode of the battery BATT, the second end of the resistor R15 and the second end of the capacitor C17 are all grounded.

[0047] like Figure 5 As shown, the present invention provides an audio playback method applicable to any of the above-mentioned outdoor high-definition screen devices, comprising: Step 510: Detect the environment of the outdoor high-definition screen device through a plurality of spectrum analyzers arranged around the outdoor high-definition screen device, and send the detected spectrum data to the microcontroller; Step 520: The microcontroller analyzes the received spectrum data, finds idle frequencies, and marks them. Step 530: The microcontroller modulates the playback frequency of the outdoor high-definition screen device to the marked idle frequency through the audio modulation circuit according to the pre-stored frequency switching strategy; In step 540, the microcontroller controls the outdoor high-definition screen device to display the marked idle frequency point at a preset position, and the audience sets the receiving frequency point of the radio terminal to the idle frequency point displayed on the outdoor high-definition screen device and then answers the call.

[0048] To facilitate understanding of the present invention, the following is a further description of the audio playback method provided by the present invention and applicable to any of the above-mentioned outdoor high-definition screen devices, based on the principle of the audio playback method of the present invention and the description of the working principle of the outdoor high-definition screen device in the embodiment.

[0049] S510 , detecting the environment in which the outdoor high-definition screen device is located by using a plurality of spectrum analyzers arranged around the outdoor high-definition screen device, and sending the detected spectrum data to the microcontroller.

[0050] Four broadband spectrum analyzers (covering the 76-88MHz FM band) are deployed in a circular pattern around the outdoor HD screen device. They are installed on the top and side brackets of the device with a spacing of ≤10 meters to ensure there are no signal blind spots.

[0051] The spectrum analyzer has a built-in RTL-SDR RF front-end with a sampling rate of 2.4MSPS and is connected to a microcontroller (STM32F407) via an SPI interface. It performs a full-band scan every 100ms, has a resolution bandwidth (RBW) of 10kHz, and a dynamic range of ≥70dB.

[0052] A magnetic loop antenna (50Ω impedance, 3dBi gain) is used and installed with vertical polarization to reduce multipath interference.

[0053] S520: The microcontroller analyzes the received spectrum data, finds an idle frequency point, and marks it.

[0054] First, the interference judgment threshold needs to be dynamically adjusted according to the environmental noise. The threshold setting formula is: ;in, is the noise influence coefficient (the default is 0.3, which is adjusted adaptively according to historical data. For example, when the noise fluctuates greatly, Adjusted from 0.3 to 0.25); Is the basic threshold (default -70dBm, can be set differently for different frequency bands); The current environmental noise intensity (collected in real time by the noise sensor); if the RSSI of a certain frequency point is ≥ , marked as "occupied"; if RSSI< , marked as "Idle"; special frequency bands (such as national radio bands) are forcibly marked as "Disabled"; select continuous idle frequency bands (such as 76.5~76.7MHz) to reduce frequency band fragmentation. In the continuous frequency band, select the frequency with the lowest RSSI as the transmission frequency point.

[0055] Use Fast Fourier Transform (FFT) to analyze spectrum data and identify idle intervals with RSSI less than -70dBm for three or more consecutive frequency points. The 76-82 MHz frequency band has low propagation loss, and the weighting factor is +20% (low frequencies are prioritized).

[0056] When a frequency point needs to be scored, the microcontroller first reads the MTBF data of the frequency point (the mean time between failures (MTBF) data of each frequency point needs to be pre-stored in the microcontroller. This data can be obtained through actual testing or based on historical experience or data provided by the manufacturer. The MTBF data is stored in numerical form and corresponds to the frequency point one by one). Then, the RSSI value of the frequency point is obtained (this can be achieved through the measurement function of the spectrum analyzer or through other methods such as network feedback or user input), and the MTBF and RSSI values are substituted into the scoring formula. Calculate and obtain the score S of the frequency point; where S is the score of the frequency point; RSSI is the received signal strength indicator; It is the weighting factor of the received signal strength indication; MTBF is the stored mean time between failures, usually 0.7; It is the weighted coefficient of the pre-stored mean time between failures, usually 0.3.

[0057] The calculated score S needs to be stored along with the corresponding frequency. The microcontroller has an internal Flash memory to store these scores and frequency data. The Flash memory is designed to hold 100 sets of frequency data, each including a frequency identifier and its corresponding score. When a new score is calculated, the microcontroller checks the available space in the Flash memory. If sufficient, the new data is written directly to the memory. If insufficient, the oldest or lowest-scoring data can be overwritten as needed. The microcontroller then selects available frequencies with scores greater than 80 as candidate frequencies.

[0058] S530, the microcontroller modulates the playback frequency of the outdoor high-definition screen device to the marked idle frequency through the audio adjustment circuit according to the pre-stored frequency switching strategy.

[0059] Specifically, the pre-stored frequency switching strategies include: S531, the microcontroller selects a frequency band containing three or more consecutive idle frequency points from the marked idle frequency points; S532, the microcontroller controls the amplifier U2 to perform gain compensation on the audio signal; S533, the microcontroller calculates the signal strength mutation rate based on the signal strength fed back by the spectrum analyzer, and determines whether the calculated signal strength mutation rate is greater than or equal to a preset mutation rate threshold; if so, proceed to S534; S534, the microcontroller controls the constant current source I1 to provide a reverse bias current for the varactor diode D2, and sets the initial capacitance value of the variable capacitor C8 to lock the target frequency band from the screened frequency bands; S535. When the microcontroller detects interference in the same frequency band, it selects the optimal frequency point for impedance matching and dynamically adjusts the capacitance value of the variable capacitor C8.

[0060] The frequency bands are prioritized dynamically, including input parameters such as real-time spectrum data (frequency, RSSI, and occupancy status) and pre-stored parameters (historical interference patterns and device transmit power limits). The sorting rules are as follows: continuous idle frequency bands > single low RSSI frequency bands (prioritizing ≥3 continuous idle frequency bands), low frequency bands (76-82MHz) > high frequency bands (83-88MHz) (low-frequency propagation loss is lower), and historical low-interference frequency bands > newly detected idle frequency bands (weighted scores based on pre-stored data).

[0061] The calculation formula of signal intensity mutation rate is: ,in, is the signal strength at the current moment; is the signal strength at the previous moment; is the time interval; The microcontroller switches the frequency band by controlling the field effect transistor Q1 of the audio switching circuit; and simultaneously updates the frequency band information displayed on the high-definition screen through the SPI interface.

[0062] In outdoor high-definition screen devices, the normal audio transmission signal strength is usually designed to be -70dBm to -50dBm. When RSSI > -60dBm is detected in a certain frequency band, it indicates the presence of an abnormally strong signal source, most likely interference from other devices in the same frequency band (such as other high-definition screens, FM radio stations) or environmental noise (such as industrial equipment). The spectrum analyzer rescans the 76-88MHz frequency band and marks the idle frequency points; adjusts the control voltage to switch to a low-interference frequency point; and reduces the transmission power according to the interference intensity to reduce secondary interference. The formula for adjusting the control voltage is: ;in, To control the voltage, it is applied to the varactor diode D2; is the target frequency (target frequency point, target frequency band); is the center frequency, is the natural oscillation frequency (the default value is usually 82MHz), which can be set by variable capacitor C8 and inductor L1; The voltage control sensitivity indicates the frequency change caused by a unit voltage change. The higher the sensitivity ( The larger the frequency deviation is, the larger the linearity may be.

[0063] The impedance matching formula is: ;in, is the target value for impedance matching; the reverse bias voltage of the varactor diode is dynamically adjusted according to the target frequency, and the capacitance value of the varactor diode D2 is changed to always match the antenna impedance.

[0064] Furthermore, the method also includes estimating the maximum audience distance d of the outdoor high-definition screen device based on the WIFI probe connected to the spectrum analyzer (by calculating the distance by counting the signal strength (RSSI) of the access device), and dynamically controlling the output power of the audio adjustment circuit based on the estimated maximum audience distance d. The specific power adjustment formula is: ,in, is the dynamic transmission power of the FM transmission circuit; is the maximum power of the amplifier, which is calculated by the power supply voltage of the amplifier (such as 12V) and the maximum current of the field effect tube Q1; k is the environmental signal loss factor, k=0.01; d is the farthest audience distance.

[0065] Figure 6 This is a structural diagram of a terminal 600 provided in an embodiment of the present invention. The terminal 600 can be used to execute the audio playback method provided in an embodiment of the present invention and applicable to any of the above-mentioned outdoor high-definition screen devices.

[0066] The terminal 600 may include a processor 610, a memory 620, and a communication module 630. These components communicate via one or more buses. Those skilled in the art will appreciate that the server structure shown in the figure does not limit the present invention. The server structure may be a bus structure or a star structure, and may include more or fewer components than shown, or combine certain components, or arrange the components differently.

[0067] Memory 620 can be used to store execution instructions of processor 610. Memory 620 can be implemented by any type of volatile or non-volatile storage device, or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic disk, or optical disk. When the execution instructions in memory 620 are executed by processor 610, terminal 600 can perform some or all of the steps in the following method embodiments.

[0068] The processor 610 is the control center of the storage terminal. It uses various interfaces and lines to connect various parts of the entire electronic terminal. It executes various functions of the electronic terminal and / or processes data by running or executing software programs and / or modules stored in the memory 620, and calling data stored in the memory. The processor can be composed of an integrated circuit (IC), for example, it can be composed of a single packaged IC, or it can be composed of multiple packaged ICs with the same or different functions. For example, the processor 610 can only include a central processing unit (CPU). In the embodiment of the present invention, the CPU can be a single computing core or multiple computing cores.

[0069] The communication module 630 is configured to establish a communication channel so that the storage terminal can communicate with other terminals, receive user data sent by other terminals, or send user data to other terminals.

[0070] The present invention also provides a computer storage medium, wherein the computer storage medium may store a program that, when executed, may include some or all of the steps of each embodiment provided herein. The storage medium may be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

[0071] Those skilled in the art will clearly understand that the techniques in the embodiments of the present invention can be implemented using software plus a necessary general-purpose hardware platform. Based on this understanding, the technical solutions in the embodiments of the present invention, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk, among other media capable of storing program code, and includes instructions for causing a computer terminal (which can be a personal computer, a server, or a second terminal, a network terminal, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention.

[0072] In this specification, the same or similar parts between the various embodiments can be referred to each other. In particular, for the terminal embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description in the method embodiment.

[0073] In the several embodiments provided by the present invention, it should be understood that the disclosed systems and methods can be implemented in other ways. For example, the system embodiments described above are merely illustrative. For example, the division of the modules is merely a logical function division. In actual implementation, there may be other division methods, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of systems or modules, and can be electrical, mechanical or other forms.

[0074] The modules described as separate components may or may not be physically separate, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed across multiple network modules. Some or all of the modules may be selected to achieve the purpose of this embodiment according to actual needs.

[0075] In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0076] Although the present invention has been described in detail with reference to the accompanying drawings and in conjunction with preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, persons of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and such modifications or substitutions shall be within the scope of the present invention. Any changes or substitutions that can be easily conceived by persons skilled in the art within the technical scope disclosed in the present invention shall be within the scope of protection of the present invention.

Claims

1. An outdoor high-definition screen device, comprising a high-definition screen body and a microcontroller connected to the high-definition screen, characterized in that: It also includes an audio adjustment circuit that is connected to the microcontroller. The audio adjustment circuit is used to modulate the audio that matches the video played on the high-definition screen body according to the control signal of the microcontroller, and send the modulated audio to the audience's radio terminal.

2. The outdoor high-definition screen device according to claim 1, characterized in that: The audio adjustment circuit includes an audio amplifier circuit, an FM transmitter circuit and a power supply circuit for powering the entire audio adjustment circuit; the input end of the audio amplifier circuit is connected to an external audio signal source device, the output end of the audio amplifier circuit is connected to the input end of the FM transmitter circuit, and the output end of the FM transmitter circuit is wirelessly connected to the audience's radio terminal.

3. The outdoor high-definition screen device according to claim 1, characterized in that: The audio amplifier circuit includes a left channel interface LINE-L, a right channel interface LINE-R, a capacitor C1, a resistor R1, a capacitor C2, a resistor R2, a resistor R3, an audio amplifier U1, a capacitor C3, a variable resistor R4, a capacitor C4, and a resistor R5; The input end of the left channel interface LINE-L and the input end of the right channel interface LINE-R are both connected to an external audio signal source device, the output end of the right channel interface LINE-R is connected to the first end of the resistor R1 through the capacitor C1, the output end of the left channel interface LINE-L is connected to the first end of the resistor R2 through the capacitor C2, the second end of the resistor R1 and the second end of the resistor R2 are both connected to the inverting input end of the audio amplifier U1 and the first end of the resistor R3, the non-inverting input end of the audio amplifier U1 is connected to the FM transmitting circuit, the output end of the audio amplifier U1 is connected to the second end of the resistor R3 and the first end of the capacitor C3, the second end of the capacitor C3 is connected to the first end of the variable resistor R4, the second end of the variable resistor R4 is grounded, the active end of the variable resistor R4 is connected to the first end of the resistor R5 through the capacitor C4, and the second end of the resistor R5 is connected to the FM transmitting circuit.

4. The outdoor high-definition screen device according to claim 3, characterized in that: The FM transmitting circuit includes a variable resistor R6, an amplifier U2, a resistor R7, a capacitor C5, a constant current source I1, a diode D1, a resistor R8, a capacitor C6, an amplifier U3, a resistor R9, a variable resistor R10, a resistor R11, a varactor diode D2, a capacitor C7, a variable capacitor C8, an inductor L1, a capacitor C9, a resistor R12, a field effect transistor Q1, a capacitor C10, a capacitor C11, a magnetic core inductor L2, a capacitor C12, a resistor R13, a transistor Q2, a capacitor C13, a coupling transformer B1, an antenna ANT1 and a capacitor C14; The inverting input of the amplifier U2 is connected to the active end of the variable resistor R6, the non-inverting input of the amplifier U2 is connected to the non-inverting input of the audio amplifier U1, the first end of the variable resistor R6, the non-inverting input of the amplifier U3, the first end of the resistor R7, the first end of the capacitor C5, the first end of the constant current source I1 and the positive electrode of the diode D1, the output of the amplifier U2 is connected to the second end of the resistor R8 and the first end of the capacitor C6, the second end of the capacitor C6 is connected to the second end of the resistor R7, the second end of the capacitor C5, the second end of the constant current source I1 and the negative electrode of the diode D1; the inverting input of the amplifier U3 is connected to the second end of the resistor R5, the output of the amplifier U3 is connected to the first end of the resistor R9, the first end of the resistor R10 and the first end of the resistor R11, the second end of the resistor R9 is connected to the inverting input of the amplifier U3, and the second end of the resistor R10 is connected to the second end of the variable resistor R6; The second end of the resistor R11 is connected to the cathode of the varactor diode D2 and the first end of the capacitor C7, the second end of the capacitor C7 is connected to the first end of the variable capacitor, the first end of the inductor L1 and the first end of the capacitor C9, the second end of the capacitor C9 is connected to the first end of the resistor R12, the first end of the capacitor C10 and the gate of the field effect transistor Q1, the second end of the capacitor C10 is connected to the first end of the capacitor C11, the first end of the magnetic core inductor L2, the source of the field effect transistor Q1 and the first end of the capacitor C12, the second end of the capacitor C12 is connected to the first end of the resistor R13 and the base of the transistor Q2, the anode of the varactor diode D2, the second end of the variable capacitor C8, the second end of the inductor L1, the second end of the resistor R12, the second end of the capacitor C11, the The second end, the second end of the resistor R13, and the emitter of the transistor Q2 are all grounded. The collector of the transistor Q2 is connected to the first end of the capacitor C13 and the first end of the primary coil of the coupling transformer B1. The second end of the capacitor C13 is connected to the second end of the primary coil of the coupling transformer B1. The drain of the field effect transistor Q1 and the active end of the primary coil of the coupling transformer B1 are both connected to the power supply circuit and grounded through the capacitor C14. The first end of the secondary coil of the coupling transformer B1 is connected to the input end of the antenna ANT. The second end of the secondary coil of the coupling transformer B1 and the ground end of the antenna ANT are both grounded. The output end of the antenna ANT is wirelessly connected to the viewer's radio terminal. The constant current source I1, the varactor diode D2, and the variable capacitor C8 are all communicatively connected to the microcontroller.

5. The outdoor high-definition screen device according to claim 4, characterized in that: The power supply circuit includes capacitor C15, resistor R14, capacitor C16, resistor R15, capacitor C17, three-hole power interface P1 and battery BATT; The first end of the three-hole power interface P1, the first end of the capacitor C15, the first end of the resistor R14, the first end of the capacitor C16 and the drain of the field effect transistor Q1 are all connected to the external power supply VCC, the second end of the capacitor C15 and the second end of the capacitor C16 are both grounded, the second end of the resistor R14 is connected to the first end of the resistor R15 and the first end of the capacitor C17, the second end of the three-hole power interface P1 is connected to the positive pole of the battery BATT, and the third end of the three-hole power interface P1, the negative pole of the battery BATT, the second end of the resistor R15 and the second end of the capacitor C17 are all grounded.

6. An audio playback method applicable to the outdoor high-definition screen device according to any one of claims 1 to 5, characterized in that: include: The environment of the outdoor high-definition screen device is detected by several spectrum analyzers arranged around the outdoor high-definition screen device, and the detected spectrum data is sent to the microcontroller; The microcontroller analyzes the received spectrum data, finds the idle frequency points and marks them; The microcontroller modulates the playback frequency of the outdoor high-definition screen device to the marked idle frequency through the audio adjustment circuit according to the pre-stored frequency switching strategy; The microcontroller controls the outdoor high-definition screen device to display the marked idle frequency points at a preset position, and the audience sets the receiving frequency point of the radio terminal to the idle frequency point displayed in the outdoor high-definition screen device and then answers the call.

7. The audio playback method according to claim 6, characterized in that: The pre-stored frequency switching strategies include: The microcontroller selects a frequency band containing three or more consecutive idle frequency points from the marked idle frequency points; The microcontroller controls amplifier U2 to perform gain compensation on the audio signal; The microcontroller calculates the signal strength mutation rate according to the signal strength fed back by the spectrum analyzer, and determines whether the calculated signal strength mutation rate is greater than or equal to a preset mutation rate threshold; If so, the microcontroller controls the constant current source I1 to provide a reverse bias current to the varactor diode D2 and sets the capacitance value of the initial variable capacitor C8 to lock the target frequency band from the screened frequency bands; When the microcontroller detects interference in the same frequency band, it selects the optimal frequency point for impedance matching and dynamically adjusts the capacitance value of the variable capacitor C8.

8. The audio playback method according to claim 6, characterized in that: It also includes estimating the farthest audience distance d of the outdoor high-definition screen device based on the WIFI probe connected to the spectrum analyzer, and dynamically controlling the output power of the audio adjustment circuit based on the estimated farthest audience distance d.

9. A terminal, characterized in that: include: processor; a memory for storing execution instructions of the processor; The processor is configured to execute the method according to any one of claims 6 to 8.

10. A computer-readable storage medium storing a computer program, characterized in that: When the program is executed by a processor, the method according to any one of claims 6 to 8 is implemented.

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