Abnormity monitoring and warning system based on DRM digital amplitude modulation broadcast signals

Abstract

The invention relates to the technical field of broadcasting, and discloses an abnormity monitoring and warning system based on DRM digital amplitude modulation broadcasting signals, which comprises a control main board, a delay warning setting board, an audio amplitude display board, a tuning screen board and a power supply module, the control main board adopts a main control chip of a high-performance single-chip microcomputer for logic control; the delay alarm setting board is composed of a TM1637 LED drive control special circuit, an LED nixie tube and four function keys. The audio amplitude display panel monitors the audio amplitudes of the signal source signal and the tuning signal in real time through two independent signal processing channels; the tuning screen board comprises a high-precision display unit and a multifunctional control panel. The DRM digital amplitude modulation broadcast audio signal can be received and demodulated without changing a broadcast link of an original transmitting station, whether the signal source audio of the transmitting station and the received audio signal break down or not is monitored and analyzed, the corresponding audible and visual alarm information is sent out when the fault occurs, and the manual inspection intensity is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the field of broadcasting technology, and in particular, to an abnormal monitoring and warning system based on DRM digital amplitude modulation broadcast signals. Background Art

[0002] In recent years, the Medium Wave General Station of Guangdong Province has proved through the broadcast test of DRM digital amplitude modulation that: DRM digital medium wave has obvious improvements in terms of coverage listening effect, power consumption, and electromagnetic interference compared with AM signals. Under the premise of the same coverage range, the energy consumption can be saved by about 55%. Digital medium wave has many advantages over traditional AM amplitude modulation broadcasts, and it is imperative to popularize digital medium wave nationwide. At present, since there are few domestic digital medium wave audience customers, the high upfront investment in R & D and production equipment has led to a monotonous variety of tuners that can receive DRM digital amplitude modulation broadcasts and high selling prices. Even no DRM digital amplitude modulation broadcast tuner that can be used in computer room cabinets has been found, and there is no equipment with functions such as monitoring and warning of DRM digital broadcast signals. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the above technical defects and provide an abnormal monitoring and warning system based on DRM digital amplitude modulation broadcast signals.

[0004] To solve the above problems, the technical solution of the present invention is: an abnormal monitoring and warning system based on DRM digital amplitude modulation broadcast signals, including a control main board, a delay warning setting board, an audio amplitude display board, a tuning screen board, and a power supply module;

[0005] The control main board uses a main control chip of a high-performance single-chip microcomputer STM32F103RTC6 for logic control. A variety of peripheral circuits are designed around the control main board, including a single-chip microcomputer module circuit, a tuning signal receiving circuit, a transmitting station signal source and tuning audio signal processing circuit, a crystal oscillator circuit, and an RTC clock circuit;

[0006] The delay warning setting board consists of a TM1637 LED driving control dedicated circuit, an LED digital tube, and four function keys;

[0007] The audio amplitude display board is constructed based on an LM3914 dot / bar display driving chip, and the audio amplitudes of the signal source signal and the tuning signal are monitored in real time through two independent signal processing channels;

[0008] The tuning screen board includes a high-precision display unit and a multi-functional control panel.

[0009] Furthermore, the tuning signal receiving circuit is equipped with a DRM1000 broadcast receiver module. The module adopts a pre-programmed software and hardware integrated architecture and can be seamlessly connected to the control main board through a standard SPI / UART interface;

[0010] The signal source of the transmitting station and the tuned audio signal processing circuit: The audio signal output interface of the signal source of the transmitting station is directly connected by line, maintaining the original signal output, ensuring that the original signal link is not modified at all, and guaranteeing the stability and continuity of the entire transmitting system; The tuned audio signal processing circuit adopts an optimized design of a dual-channel low-noise operational amplifier OPA1656 combined with a first-order passive RC high-pass filter to process and output the demodulated signal;

[0011] The crystal oscillator circuit and the RTC clock circuit: The crystal oscillator circuit serves as the main clock source of the single-chip microcomputer, providing an accurate frequency signal to ensure the system operation timing; The RTC clock circuit is responsible for providing an accurate timestamp for storing abnormal information and storing this data into the memory card.

[0012] Furthermore, the high-precision display unit uses a 1.3-inch IPS liquid crystal screen, communicates efficiently with the control main board through the I2C bus protocol, and adopts a dual-address mode, allowing intelligent avoidance of address conflicts when controlling multiple functions simultaneously; The multifunctional control panel integrates 12 lockless buttons, including core functions such as volume adjustment, channel switching, automatic channel search, and standby wake-up. Among them, the band selection button and the format switching button adopt a hardware debounce circuit, and the response time is less than 30 ms.

[0013] Furthermore, the four function keys of the delay alarm setting board are respectively Time +, Time -, Signal Source / Tuning Signal Switching, and Delay Time / Intensity Display Switching. The delay alarm setting board interacts with the control main board through the I2C communication protocol, and the four function keys respectively correspond to the dual-channel independent delay settings of the station signal source and the tuning signal, as well as displaying the current intensity of the audio signal or the delay alarm time.

[0014] Furthermore, the single-ended audio signal input to the audio amplitude display board is mapped to the on / off state of the LED through the comparator and reference voltage inside the LM3914, driving the dynamic display of a double-row 10-segment LED light column. The duty officer can quickly identify sudden volume changes or noise interference through the fluctuation of the light bar.

[0015] Furthermore, the system uses a high-impedance coupling circuit to divide the signal source audio of the transmitting station into two paths for processing: One is the main link direct-through channel, which uses a high-impedance coupling circuit to ensure distortion-free transmission of the signal to the original signal source link. The other path of the signal is converted from the differential signal built into the control main board to a single-ended signal and input into the control chip and the audio amplitude display board;

[0016] In terms of monitoring DRM digital amplitude modulation broadcast signals broadcast by the transmitting station, the broadcast signals are demodulated through the DRM1000 chip and its peripheral circuits. The demodulated signals are divided into three paths: one path is output to the audio amplitude display board for monitoring the signal status and displaying the real-time intensity of the signal; the other two paths are output to the audio processing circuit in the main control board, converted into differential signals and balanced 600-ohm audio signals, and output through the audio output interface to replace the original demodulation equipment in the machine room, facilitating the duty personnel to monitor and ensuring the clarity and quality of the signals.

[0017] The main control chip is responsible for real-time monitoring of the signal source audio signal and the tuned audio signal. Once a fault is detected in a certain signal, the system will start the timer to start timing. If the time set by the delay alarm setting board arrives, the system will start the alarm mechanism, output a +3.3V TTL pulse signal to drive the buzzer circuit to emit an alarm sound, and at the same time control the indicator light on the audio amplitude display board to flash for prompt, achieving the effect of audible and visual alarm, so as to remind the duty personnel to pay attention to the fault situation. At the same time, a +3.3V signal is output from the abnormal alarm signal output interface, and the station can be connected to the original alarm system according to actual needs.

[0018] The advantages of the present invention compared with the existing technology are as follows: This system can receive and demodulate DRM digital amplitude modulation broadcast audio signals, monitor and analyze whether there are faults in the signal source audio and received audio signals of the transmitting station, and send corresponding audible and visual alarm information when a fault occurs without changing the original broadcast link of the transmitting station, effectively reducing the intensity of manual inspection and providing more powerful security broadcast guarantee for the transmitting stations with digital amplitude modulation broadcasts. Brief Description of the Drawings

[0019] Figure 1 It is the system structure diagram of the present invention.

[0020] Figure 2 It is the circuit diagram of the main control chip of the present invention.

[0021] Figure 3 It is the tuned audio signal processing circuit of the present invention. Detailed Embodiments

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

[0023] Such as Figures 1 to 3As shown in the figure, an abnormal monitoring and warning system based on DRM digital amplitude modulation broadcast signals adopts a modular design, which is easy to maintain and upgrade, and further enhances reliability. The system consists of a control main board, a delay warning setting board, an audio amplitude display board, a tuning screen board, and a power module. The system interfaces include the audio input of the station signal source, the audio output of the signal source, the audio output of the tuning signal *2, the abnormal warning signal output, the RS-232 communication interface, the external antenna interface *2, and the 220V power input. The system can display and set the intensity and amplitude of the received and demodulated radio broadcast signals, can set to monitor the signal source and demodulated signals of the transmitting station separately or simultaneously, and set the delay warning time, etc., providing a powerful fault warning guarantee for the computer room duty.

[0024] This system uses the low-cost and high-reliability single-chip microcomputer STM32F103RTC6 as the core controller and adopts a dual-channel signal isolation architecture to achieve safety monitoring. In order to ensure the quality and stability of the signal source audio, the system uses a high-impedance coupling circuit to divide the signal source audio of the transmitting station into two channels for processing: one is the main link direct-through channel, which uses a high-impedance coupling circuit to ensure that the signal is transmitted to the original signal source link without distortion, and the other signal is converted from the differential signal built into the control main board into a single-ended signal and input into the control chip and the audio amplitude display board.

[0025] In terms of monitoring the DRM digital amplitude modulation broadcast signals broadcast by the transmitting station, the broadcast signals are demodulated by the DRM1000 chip and its peripheral circuits. The demodulated signals are divided into three channels: one channel is output to the audio amplitude display board for monitoring the signal status and displaying the real-time intensity of the signal; the other two channels are output to the audio processing circuit in the control main board, converted into differential signals and balanced 600-ohm audio signals, and output through the audio output interface to replace the original demodulation equipment in the computer room, facilitating the duty personnel to listen and ensuring the clarity and quality of the signal.

[0026] The main control chip is responsible for real-time monitoring of the signal source audio signal and the tuning audio signal. Once a fault is detected in a certain signal, the system will start the timer to start timing. If the time set by the delay warning setting board arrives, the system will start the warning mechanism, output a +3.3V TTL pulse signal to drive the buzzer circuit to emit an alarm sound, and at the same time control the indicator light on the audio amplitude display board to flash for prompt, achieving the effect of sound and light warning, so as to remind the duty personnel to pay attention to the fault situation. At the same time, the abnormal warning signal output interface outputs a +3.3V signal, and the station can be connected to the original alarm system according to actual needs.

[0027] To improve the compatibility and expandability of the system, the system also designs an RS-232 interface and a digital output, which provides a convenient signal source for subsequent possible functions such as adding external alarms, making the system have higher flexibility and the possibility of future upgrades.

[0028] The core control unit of this system is the control main board, which uses the high-performance single-chip microcomputer STM32F103RTC6 chip for logic control. This chip integrates a 12-bit successive approximation ADC, supports a maximum of 16 channels and a sampling capacity of 1MSPS, fully meeting the radio and television-level audio standard and ensuring the accurate acquisition and processing of audio signals. To ensure the stable operation of the system and the integrity of its functions, a variety of peripheral circuits are designed around the control main board, including a crystal oscillator circuit to ensure the stability of the system clock, a tuning signal receiving circuit for receiving and processing DRM digital amplitude modulation broadcast signals or traditional broadcast signals, a transmitting station signal source differential input to single-ended signal circuit and a tuning signal to differential output circuit for optimizing signal quality, effectively suppressing common-mode interference, reducing the impact of external noise on audio signals, and ensuring the anti-interference ability of the signal. In addition, the system is also equipped with a power supply circuit for converting 18V to 5V and 5V to 3.3V, a buzzer circuit for fault alarms, an RTC clock circuit for providing real-time time information to the control chip, a TF card slot for recording signal strength and abnormal data, reserved power test lights and debugging resistors for system debugging, and all interface terminals are reserved with idle control pins, improving the compatibility and expandability of the system. The design of these circuits aims to ensure the stability and performance of the system, and also provides convenience for future function expansion.

[0029] Single-chip microcomputer module circuit: As Figure 2 shown, the pin function definitions of the system single-chip microcomputer STM32F103RTC6 chip are described as follows:

[0030] PC6 = DES, PC7 = RSTN, representing the detection of the audio of the transmitting station signal source and the tuning audio input; PB12 = SDI, PB13 = SCK, PB14 = LOAD, PB15 = ADD, PC6 = DES, representing the communication interface, load, input of delay time information and display of the delay alarm setting board; PB8 = WARN1, PB9 = WARN2, representing the output interface of the abnormal alarm signal to output a +3.3v signal, PB3 = WARNING, PB4 = WARNLED, representing a +3.3V TTL pulse signal and controlling the indicator light of the audio amplitude display board to flash for prompt.

[0031] The tuning signal receiving circuit is equipped with a DRM1000 broadcast receiver module. This module adopts a pre-programmed software-hardware integrated architecture and can be seamlessly connected to the control main board through standard SPI / UART interfaces, achieving fast integration of "plug and play". The wideband RF front-end of the receiver module covers the entire spectrum from 530 kHz to 108 MHz and can be used globally across the MF, HF, and VHF bands. It can adaptively decode AM, FM, DRM, and all DRM digital broadcast signals (including the strong anti-interference transmission of DRM30 in the medium and short wave bands and the high-definition stereo broadcast of DRM+ in the FM band). This receiving module not only has powerful hardware performance but also incorporates all software and necessary intellectual property licenses, including the xHE-AAC encoding and decoding technology required by digital radio standards, providing higher audio quality and lower bitrates, which helps to achieve more efficient audio transmission in receiving devices.

[0032] Transmitter station signal source and tuning audio signal processing circuit: The audio signal output interface of the transmitter station signal source is directly connected by a line, maintaining the original signal output, ensuring that the original signal link remains unchanged, and guaranteeing the stability and continuity of the entire transmission system. Another audio signal is input in parallel to the differential-to-single-ended signal circuit. This circuit uses the INA137UA differential line receiver, which can not only efficiently convert balanced differential signals into single-ended signals but also has strong anti-interference capabilities, effectively suppressing common-mode noise and greatly improving the anti-interference ability in the complex electromagnetic environment within the transmitter station, ensuring the integrity and accuracy of the original source signal. The converted single-ended signal is used for controlling the audio state acquisition of the chip and driving the audio display.

[0033] The tuning audio signal processing circuit uses a dual-channel low-noise operational amplifier OPA1656 in cooperation with a first-order passive RC high-pass filter for optimized design to process and output the demodulated signal. The demodulated baseband signal first effectively filters out the carrier residual low-frequency noise and the complex environmental power frequency interference of the transmitter station through the first-order passive RC high-pass filter; then it is connected to the dual-op amp differential drive circuit composed of OPA1656. Utilizing its ultra-low distortion characteristics and wide bandwidth characteristics, through a precision matching resistor network, signal amplitude amplification and phase complementary output are achieved, and finally a low-distortion balanced differential signal is generated. The impedance of this circuit is as low as 2Ω, which can directly drive high-sensitivity audio devices or high-speed ADC sampling modules, significantly improving the signal-to-noise ratio and anti-power frequency interference ability of the broadcast signal monitoring system. The system can directly replace the original traditional broadcast tuning equipment for the duty personnel in the machine room to monitor the high-fidelity broadcast signal in real time.

[0034] Crystal Oscillator Circuit and RTC Clock Circuit: To ensure the accuracy of the system time, a dual-power supply mechanism is adopted in the system design. The real-time clock chip (DS1302) is independently powered by a button battery and the main power supply module, ensuring that time information can be continuously updated and stored even when the main power supply is cut off. The crystal oscillator circuit serves as the main clock source of the single-chip microcomputer, providing an accurate frequency signal to ensure the system operation timing; while the RTC clock is responsible for providing an accurate timestamp for storing abnormal information and storing this data in the memory card to meet the requirement that the abnormal program record information in the radio and television safe broadcast management regulations should be preserved for more than one year.

[0035] The tuning screen board, as the core module of human-computer interaction, consists of a high-precision display unit and a multi-functional control panel working together. The display part uses a 1.3-inch IPS liquid crystal screen, which communicates efficiently with the control main board through the I2C bus protocol and adopts a dual-address mode, allowing intelligent avoidance of address conflicts when controlling multiple functions simultaneously. There are 12 lockless buttons integrated on the board, including core functions such as volume adjustment (±3dB step), channel switching (0.1MHz fine tuning), automatic channel search (SCAN), standby wake-up (STANDBY), etc. Among them, the band selection key (MF / HF / VHF) and the system switching key (AM / FM / DRM) adopt a hardware debounce circuit with a response time of less than 30ms to ensure the reliability of high-frequency operations.

[0036] The core of the delay alarm setting board consists of a dedicated circuit for TM1637 LED drive control, an LED digital tube, and 4 function buttons. This module interacts with the control main board through the I2C communication protocol. The four function keys (Time +, Time -, Signal Source / Tuning Signal Switching, Delay Time / Intensity Display Switching) respectively correspond to the dual-channel independent delay setting of the station signal source and the tuning signal, and display the current intensity of the audio signal or the delay alarm time. After setting the delay parameters through the buttons, the TM1637 chip will drive the digital tube to display the countdown value in real time and transmit it to the main control chip through a data frame (including channel identifier, time value, and CRC check code). During system operation, the main control chip continuously monitors the status of the two signals. Suppose the signal source monitoring is set to alarm after a 2S delay and the tuning signal is set to alarm after a 10S delay: when an abnormality in the station signal source is detected, only an abnormal audible and visual alarm is triggered after the countdown ends; if a fault occurs in the tuning signal, a 10-second delay logic is activated. If the station tuning signal is still silent within 10 seconds, it is confirmed as a persistent fault, and the main control chip will drive the buzzer and the LED warning light.

[0037] The audio amplitude display board is built based on the LM3914 dot / bar display driver chip, and monitors the audio amplitude of the signal source signal and the tuning signal in real time through two independent signal processing channels. The input single-ended audio signal is mapped to the LED on and off state through the comparator and reference voltage inside the LM3914, driving the double-row 10-segment LED light column for dynamic display. The on-duty personnel can quickly identify sudden changes in volume or noise interference through the fluctuations of the light bar. An intelligent two-color button is configured next to each display module. Under normal circumstances, green indicates that the signal is stable. When an abnormal amplitude is detected (such as signal loss, overload), the button automatically switches to red breathing light mode, and cooperates with triggering a buzzer pulse alarm to remind the on-duty personnel and assist in identifying faults, significantly improving the inspection efficiency and fault location accuracy of the equipment in the computer room.

[0038] The system uses C language to program the main control chip STM32F103RTC6 to realize real-time monitoring of the signal source audio signal and the demodulated DRM audio signal, and to issue an audible and visual alarm command when a fault occurs and meets the set delay time to remind the on-duty personnel.

[0039] The system can receive and demodulate DRM digital AM broadcast audio signals, monitor and analyze whether there are any faults in the transmitter station signal source audio and the received audio signal without changing the broadcast link of the original transmitter station, and issue corresponding sound and light alarm information when a fault occurs, providing more powerful safe broadcasting protection for transmitter stations with digital AM broadcasting.

[0040] The system can clearly receive DRM digital AM broadcast signals, effectively identify and monitor the audio signal and broadcast signal of the signal source of the transmitting station, and issue an audible and visual alarm prompt in case of failure, effectively reducing the intensity of manual inspections. The system adopts a modular design and reserves an RS-232 industrial standard interface. Its protocol compatibility lays the foundation for subsequent upgrades. With the help of artificial intelligence technology, it realizes intelligent diagnostic functions such as fault root cause location.

[0041] The system's scalable architecture is deeply aligned with the technical path of "promoting the intelligent upgrade of infrastructure such as transmitters and monitoring stations". Its AI fusion design directly responds to the plan's requirement of "building a safe broadcast guarantee system with data as the core and intelligent algorithms as the driving force", providing key technical support for the radio and television industry to explore the next generation of smart stations.

[0042] The undisclosed parts in the present invention are all prior art, and their specific structures and working principles are not described in detail.

[0043] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, such that a process, method, article or device comprising a series of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article or device.

[0044] Although embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, and the scope of the invention is defined by the appended claims and their equivalents.

[0045] The above description of the present invention and its embodiments is not restrictive. What is shown in the drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. In general, if those of ordinary skill in the art are inspired by it and, without departing from the purpose of the present invention, design similar structural modes and embodiments to this technical solution without creative efforts, they should all fall within the protection scope of the present invention.

Claims

1. An abnormal monitoring and alarm system based on DRM digital amplitude modulation broadcasting signals, characterized in that: It includes a control main board, a delay alarm setting board, an audio amplitude display board, a tuning screen board and a power module; The control mainboard uses the high-performance single-chip STM32F103RTC6 main control chip for logic control. A variety of peripheral circuits are designed around the control mainboard, including single-chip module circuit, tuning signal receiving circuit, transmitting station signal source and tuning audio signal processing circuit, crystal oscillator circuit and RTC clock circuit; The delayed alarm setting board is composed of TM1637LED drive control dedicated circuit, LED digital tube, and four function buttons; The audio amplitude display board is built based on the LM3914 dot / bar display driver chip, and monitors the audio amplitude of the source signal and the tuning signal in real time through two independent signal processing channels; The tuning screen panel includes a high-precision display unit and a multi-function control panel.

2. The abnormality monitoring and alarm system based on DRM digital amplitude modulation broadcasting signal according to claim 1 is characterized in that: The tuning signal receiving circuit is equipped with the DRM1000 broadcast receiver module, which adopts a pre-programmed hardware and software integrated architecture and can be seamlessly connected to the control motherboard through a standard SPI / UART interface; The signal source of the transmitting station and the tuning audio signal processing circuit, the audio signal output interface of the signal source of the transmitting station is directly connected to the line, maintaining the original signal output, ensuring that the original signal link is not modified in any way, and ensuring the stability and continuity of the entire transmitting system; The tuned audio signal processing circuit uses a dual-channel low-noise operational amplifier OPA1656 with an optimized design of a first-order passive RC high-pass filter to process and output the demodulated signal; Crystal oscillator circuit and RTC clock circuit. The crystal oscillator circuit serves as the main clock source of the microcontroller and provides accurate frequency signals to ensure the system operation timing. The RTC clock circuit is responsible for providing accurate timestamps for storing abnormal information and storing the data in the memory card.

3. The abnormality monitoring and alarm system based on DRM digital amplitude modulation broadcasting signal according to claim 1 is characterized in that: The high-precision display unit uses a 1.3-inch IPS LCD screen, which achieves efficient communication with the control mainboard through the I2C bus protocol and adopts a dual-address mode, allowing intelligent avoidance of address conflicts when controlling multiple functions at the same time; the multi-function control panel integrates 12 unlocked buttons, including core functions such as volume adjustment, channel switching, automatic channel search, and standby wake-up. The band selection key and system switch key use hardware de-bouncing circuits with a response time of less than 30ms.

4. The abnormality monitoring and alarm system based on DRM digital amplitude modulation broadcasting signal according to claim 1 is characterized in that: The four function keys of the delay alarm setting board are time +, time -, signal source / tuning signal switching, and delay time / intensity display switching. The delay alarm setting board interacts with the control main board through the I2C communication protocol. The four function keys correspond to the dual-channel independent delay settings of the station signal source and tuning signal, and display the current intensity of the audio signal or the delay alarm time.

5. The abnormal monitoring and alarm system based on DRM digital amplitude modulation broadcasting signal according to claim 1 is characterized in that: The single-ended audio signal input by the audio amplitude display board is mapped to the LED on / off status through the comparator and reference voltage inside the LM3914, driving the double-row 10-segment LED light bar for dynamic display. The on-duty personnel can quickly identify sudden changes in volume or noise interference through the fluctuations of the light bar.

6. An abnormality monitoring and alarm system based on DRM digital amplitude modulation broadcasting signals according to any one of claims 1 to 5, characterized in that: The system uses a high-impedance coupling circuit to divide the signal source audio of the transmitting station into two channels for processing: one channel is the main link direct channel, and a high-impedance coupling circuit is used to ensure that the signal is transmitted to the original signal source link without distortion, and the other channel is converted into a single-ended signal through the differential signal built into the control mainboard and input into the control chip and the audio amplitude display board; In terms of monitoring the DRM digital AM broadcasting signals broadcast by the transmitter station, the broadcasting signals are demodulated by the DRM1000 chip and its peripheral circuits. The demodulated signals are divided into three paths: one path is output to the audio amplitude display board to monitor the signal status and display the real-time strength of the signal; the other two paths are output to the audio processing circuit in the control main board, converted into differential signals and balanced 600-ohm audio signals, and output through the audio output interface to replace the original demodulation equipment in the machine room, so that the on-duty personnel can monitor and ensure the clarity and quality of the signal; The main control chip is responsible for real-time monitoring of the signal source audio signal and the tuned audio signal. Once a signal fault is detected, the system will start the timer to start timing. If the time set by the delayed alarm setting board is reached, the system will start the alarm mechanism and output a +3.3VTTL pulse signal to drive the buzzer circuit to sound an alarm. At the same time, it controls the indicator light of the audio amplitude display board to flash to achieve the effect of sound and light alarm, thereby reminding the on-duty personnel to pay attention to the fault. At the same time, the abnormal alarm signal output interface outputs a +3.3v signal, and the station can be connected to the original alarm system according to actual needs.

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