An emergency broadcast terminal supporting remote controllable medium wave amplitude modulation

Abstract

The utility model relates to the technical field of emergency broadcasting, and specifically discloses an emergency broadcasting terminal supporting remote controllable medium wave amplitude modulation, including an AM receiving module, an audio ADC / DAC module, an FPGA module, a main control MCU, an audio mixing and amplifying module, an amplifier module, and a loudspeaker; the main control MCU is respectively connected to the AM receiving module, the audio ADC / DAC module, the FPGA module, the audio mixing and amplifying module, and the amplifier module, the AM receiving module is connected to the audio ADC / DAC module, the audio ADC / DAC module is connected to the FPGA module, the audio mixing and amplifying module is respectively connected to the audio ADC / DAC module, the main control MCU, and the amplifier module, and the amplifier module is connected to the loudspeaker. The utility model transmits sound and control signals in the form of IP network broadcasting and medium wave amplitude modulation broadcasting, and finally realizes the transmission of important sound information to users, so as to achieve the purpose of daily broadcasting and emergency warning.

Description

Technical Field

[0001] The utility model relates to the technical field of emergency broadcasting, and more specifically, to an emergency broadcasting terminal supporting remotely controllable medium wave amplitude modulation. Background Art

[0002] Emergency broadcasting refers to providing a fast and convenient information transmission channel when a major natural disaster, emergency, public health, social security or other public crisis occurs. Emergency broadcasting has the characteristics of wide coverage and normalization. In the broadcasting system, the terminal is the key device that transmits information to the user. In daily use, emergency broadcasting terminals are mainly used to play regular programs such as music, news, entertainment, etc., and to release important information in emergency situations, such as natural disaster warnings, public safety incident notifications, etc.

[0003] MSK (Minimum Shift Keying) is a digital modulation technique used to transmit digital information in digital communications. AM is an analog modulation technique commonly used in broadcasting and wireless communications. Adding MSK signals to AM can have the following benefits:

[0004] (1) High spectrum efficiency: The spectrum efficiency of MSK signals is higher than that of traditional AM signals. Since the spectrum occupied by MSK signals is narrower, more information can be transmitted within a limited frequency band.

[0005] (2) Strong anti-interference ability: MSK signals have good anti-interference performance. Due to the spectrum characteristics of MSK signals, they have strong anti-interference ability against frequency offset and phase offset, and can effectively resist noise and interference in the channel.

[0006] (3) Low bit error rate: MSK signals have a low bit error rate during transmission. Due to the modulation method of MSK signals, they have a good tolerance for clock offset and phase offset during transmission, which can reduce the bit error rate.

[0007] (4) Simple implementation: MSK modulation technology is relatively simple and has low implementation cost. The modulation and demodulation process of MSK signals is relatively simple and can be implemented through simple digital circuits or software algorithms.

[0008] Currently, the AM receivers on the market mainly receive AM audio signals, and cannot remotely control the terminal to play audio. Summary of the invention

[0009] The utility model provides an emergency broadcast terminal supporting remote controllable medium wave amplitude modulation, so as to solve the problem in the prior art that the terminal cannot be remotely controlled to broadcast audio.

[0010] As a first aspect of the utility model, there is provided an emergency broadcast terminal supporting remote controllable medium wave amplitude modulation, comprising an AM receiving module, an audio ADC / DAC module, an FPGA module, a main control MCU, an audio mixing and amplifying module, a power amplifier module and a speaker; the main control MCU is respectively communicated with the AM receiving module, the audio ADC / DAC module, the FPGA module, the audio mixing and amplifying module and the power amplifier module, the AM receiving module is communicated with the audio ADC / DAC module, the audio ADC / DAC module is communicated with the FPGA module, the audio mixing and amplifying module is respectively communicated with the audio ADC / DAC module, the main control MCU and the power amplifier module, and the power amplifier module is connected to the speaker.

[0011] Furthermore, the AM receiving module includes a KT0913 chip.

[0012] Furthermore, the audio ADC / DAC module includes an ALC5616 chip.

[0013] Furthermore, the audio mixing and amplifying module includes a 74hc4052 analog switch chip and a NE5532 operational amplifier.

[0014] The emergency broadcast terminal supporting remote controllable medium wave amplitude modulation provided by the utility model has the following advantages: the emergency broadcast terminal adds the transmission of MSK signals, and through the analysis of MSK signals by the FPGA module, the terminal's power on and off and other information transmission can be remotely controlled. At the same time, the emergency broadcast terminal also integrates the remote transmission of the IP network, and performs remote audio transmission of the IP channel according to the IP protocol. The terminal mainly transmits sound and control signals in the form of IP network broadcasting and medium wave amplitude modulation broadcasting, and finally realizes the transmission of important sound information to users, achieving the purpose of daily broadcasting and emergency warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention, but do not constitute a limitation to the present invention.

[0016] Figure 1 The utility model provides a circuit principle block diagram of an emergency broadcast terminal supporting remote controllable medium wave amplitude modulation.

[0017] Figure 2 The present invention provides a circuit diagram of an AM receiving module.

[0018] Figure 3 The present invention provides a circuit diagram of an audio ADC / DAC module.

[0019] Figure 4 The present invention provides a circuit diagram of an analog switch in an audio mixing and amplifying module.

[0020] Figure 5 The present invention provides a circuit diagram of an operational amplifier in an audio mixing and amplification module. DETAILED DESCRIPTION

[0021] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined purpose of the utility model, the specific implementation method, structure, characteristics and effects of the emergency broadcast terminal supporting remote controllable medium wave amplitude modulation proposed by the utility model are described in detail below in combination with the accompanying drawings and preferred embodiments. Obviously, the described embodiments are part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the utility model.

[0022] In this embodiment, an emergency broadcast terminal supporting remote controllable medium wave amplitude modulation is provided, such as Figure 1 As shown, it includes an AM receiving module, an audio ADC / DAC module, an FPGA module, a main control MCU, an audio mixing and amplifying module, a power amplifier module and a speaker; the main control MCU is respectively communicated with the AM receiving module, the audio ADC / DAC module, the FPGA module, the audio mixing and amplifying module and the power amplifier module, the AM receiving module is communicated with the audio ADC / DAC module, the audio ADC / DAC module is communicated with the FPGA module, the audio mixing and amplifying module is respectively communicated with the audio ADC / DAC module, the main control MCU and the power amplifier module, and the power amplifier module is connected to the speaker.

[0023] Specifically, the main control MCU controls the AM receiving module through the I2C bus (SDA / SCL), and the main control MCU controls the audio ADC / DAC module through the I2C bus (SDA / SCL). The audio ADC / DAC module transmits audio signals and MSK signals between the FPGA module through the I2S audio bus.

[0024] Preferably, if Figure 2 As shown, the AM receiving module includes a KT0913 chip. Under the control of the main control MCU, the AM receiving module receives an analog AM signal through an antenna, and demodulates the analog AM signal to output a demodulated analog AM signal, wherein the demodulated analog AM signal includes an analog audio signal and an analog MSK signal.

[0025] Preferably, if Figure 3As shown, the audio ADC / DAC module includes an ALC5616 chip. The audio ADC module is used to receive the demodulated analog AM signal output by the AM receiving module, convert the demodulated analog AM signal into a digital AM signal, and then transmit it to the FPGA module through the I2S audio bus; the audio DAC module is used to receive the digital audio signal separated by the FPGA, convert the digital audio signal into an analog audio signal through the I2S audio bus, and output it to the audio mixing and amplification module.

[0026] Specifically, the I2S audio bus has a total of 5 lines: two audio data lines (input / output) and three clock lines, among which I2S_LRCK indicates whether the current data line is transmitting the left channel or the right channel; I2S_BCLK coordinates the data transmission on the data line (in one clock cycle, the master control and audio codec chip obtain one bit of audio data from the audio line); I2S_MCLK is the clock supplied by the master control to the audio codec chip to maintain normal operation; I2S_DIN and I2S_DOUT are the input and output of audio data.

[0027] Preferably, the FPGA module is used to separate the digital AM signal output by the audio ADC module, and transmit the separated digital audio signal to the audio ADC / DAC module again; at the same time, it decodes the separated digital MSK signal, and then transmits the decoded digital MSK signal to the main control MCU through the serial port (TXD / RXD), so that the main control MCU can control the switching of the two audio signal channels in the audio mixing and amplification module according to the decoded digital MSK signal and the network protocol.

[0028] Specifically, the process of digital MSK signal decoding implemented by the FPGA module includes the following steps:

[0029] 1. Signal sampling: First, the received MSK modulated signal needs to be sampled. The purpose of sampling is to convert the continuous time signal into a discrete time signal for subsequent processing;

[0030] 2. Clock recovery: In MSK decoding, the clock signal used by the transmitter needs to be recovered. Clock recovery can be achieved through technologies such as PLL (Phase-Locked Loop) so that the clock of the receiver is synchronized with the transmitter;

[0031] 3. Coherent demodulation: Coherent demodulation is a key step in MSK decoding. It multiplies the received signal with the local reference signal to obtain the demodulated baseband signal. Coherent demodulation requires the use of technologies such as phase-locked loop (PLL) or correlator;

[0032] 4. Low-pass filtering: The demodulated baseband signal is filtered through a low-pass filter to remove high-frequency noise and multipath interference. Low-pass filters usually use FIR (Finite Impulse Response) or IIR (Infinite Impulse Response) structures;

[0033] 5. Clock extraction: In MSK decoding, the clock information needs to be extracted from the demodulated baseband signal. Clock extraction can be achieved through technologies such as PLL or correlator to recover the clock signal of the transmitter;

[0034] 6. Decoding: Finally, the demodulated baseband signal is converted into the original data through the decoder. The specific implementation of the decoder depends on the encoding method and protocol used.

[0035] Preferably, the main control MCU module includes Allwinner's V3S chip; (1) the main control MCU module receives the network protocol and IP digital audio signal through the IP network, performs digital-to-analog conversion on the IP digital audio digital signal, and then determines whether to transmit the IP audio signal according to the network protocol; (2) the main control MCU module controls the audio mixing and amplification module through GPIO to switch the audio priority, and sets the priority of the AM audio signal and the IP audio signal according to the data protocol; (3) the main control MCU controls the power amplifier module through GPIO, and when the audio mixing and amplification module needs to transmit the relevant audio signal, the power amplifier module is turned on to drive the speaker.

[0036] Preferably, if Figure 4-5 As shown, the audio mixing and amplification module includes a 74hc4052 analog switch chip and a NE5532 operational amplifier. Under the control of the main control MCU, the audio mixing and amplification module switches two audio signal channels (one is the AM audio signal output by the audio ADC / DAC module, and the other is the IP audio signal output by the main control MCU) according to the priority.

[0037] Preferably, the power amplifier module is used to amplify the power of the audio signal, drive the speaker, and broadcast the required audio to the audience.

[0038] The working principle of the emergency broadcast terminal supporting remote controllable medium wave amplitude modulation provided by the utility model is as follows:

[0039] (1) The AM receiving module outputs the demodulated analog AM signal to the audio ADC module. The audio ADC module converts the demodulated analog AM signal into a digital AM signal and then transmits it to the FPGA module. The FPGA module separates the digital AM signal output by the audio ADC module and transmits the separated digital audio signal to the audio DAC module. The audio DAC module converts the digital audio signal into an analog audio signal and outputs it to the audio mixing and amplification module. The main control MCU module receives the IP digital audio signal, performs digital-to-analog conversion on the IP digital audio digital signal, and then outputs the IP audio analog signal to the audio mixing and amplification module.

[0040] (2) The FPGA module decodes the separated digital MSK signal and transmits the decoded digital MSK signal to the main control MCU; the main control MCU module receives the network protocol; the main control MCU can control the switching of the two audio signal channels in the audio mixing and amplification module according to the decoded digital MSK signal and the network protocol. The main control MCU controls the audio mixing and amplification module through GPIO to switch the audio priority and sets the priority of the AM audio signal and the IP audio signal according to the data protocol;

[0041] (3) The main control MCU controls the power amplifier module through GPIO. When the audio mixing and amplification module needs to transmit relevant audio signals, the power amplifier module is turned on to drive the speaker.

[0042] The utility model provides an emergency broadcast terminal supporting remote controllable medium wave amplitude modulation, which mainly realizes remote control of AM amplitude modulation broadcasting and remote control of IP network broadcasting. Wired and wireless emergency broadcasting is realized through IP network or AM amplitude modulation, and dual modes are realized by mutual backup, and broadcasting content is broadcast according to the set priority. The terminal supports two modes, IP network and medium wave AM amplitude modulation, performs emergency broadcasting according to priority configuration, and is responsible for parsing the IP protocol and decoding the MSK signal.

[0043] The above description is only a preferred embodiment of the present invention, and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. An emergency broadcast terminal supporting remotely controllable medium wave amplitude modulation, characterized in that: It includes an AM receiving module, an audio ADC / DAC module, an FPGA module, a main control MCU, an audio mixing and amplifying module, a power amplifier module and a speaker; the main control MCU is respectively connected to the AM receiving module, the audio ADC / DAC module, the FPGA module, the audio mixing and amplifying module and the power amplifier module, the AM receiving module is connected to the audio ADC / DAC module, the audio ADC / DAC module is connected to the FPGA module, the audio mixing and amplifying module is respectively connected to the audio ADC / DAC module, the main control MCU and the power amplifier module, and the power amplifier module is connected to the speaker.

2. The emergency broadcast terminal supporting remotely controllable medium wave amplitude modulation according to claim 1, characterized in that: The AM receiving module includes a KT0913 chip.

3. The emergency broadcast terminal supporting remotely controllable medium wave amplitude modulation according to claim 1, characterized in that: The audio ADC / DAC module includes an ALC5616 chip.

4. The emergency broadcast terminal supporting remotely controllable medium wave amplitude modulation according to claim 1, characterized in that: The audio mixing and amplifying module includes a 74hc4052 analog switch chip and a NE5532 operational amplifier.

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