For radio transmitter, the controller is one of the important components, and its design and implementation also need to adhere to the concept of keeping pace with the times. With the rapid development of science and technology and the continuous improvement of radio and television requirements, it is undoubtedly of great significance to improve the stability of broadcast and television transmitters by actively developing micro controller systems in broadcast transmitters. This paper introduces the composition, system functions and technical requirements of the radio transmitter, and then makes a comprehensive analysis of the design and implementation of the radio transmitter microcontroller system from the aspects of system switch input channel design, software overall design and module programming, which provides a reference for the design and implementation of the radio transmitter microcontroller system. With the rapid development of science and technology and the continuous improvement of people’s living standard, especially the vigorous development of our economy and society, the broadcasting industry has also made great achievements.
The development of technology has promoted the development of radio broadcasting, but also brought new challenges to radio broadcasting, which requires it to develop in the direction of intellectualization [1].
In radio broadcasting transmitter, the controller is an important part. The quality of the controller is related to the quality of FM broadcasting transmitter, so we must attach great importance to it. This paper mainly discusses the design and implementation of the radio transmitter microcontroller system. As the core of radio broadcasting, the stability of transmitter system is related to the quality of radio programs.
Therefore, the core components of microcontrollers must have high stability. The stability of MCU is mainly determined by the stability of software and hardware. The microcontroller can directly start and shut down the broadcasting transmitter and change the traditional manual switch mode. At the same time, the system also has the detection function, in the process of transmitter operation, it can check each module from every detail. In data query, the function of radio broadcasting transmitter is also very powerful. It mainly includes two aspects: manual query of all data in the operation of radio transmitter, which has strong timeliness and can query the historical data of transmitter in a certain period of time, such as the number of switches, the running records of each module of the system and the analog transmitter. In setting parameters, including parameter storage and setting, scientific setting can change the start-up and shutdown time of the controller, and take 24 hours as a cycle. In a cycle, it usually needs at least four sets of switch-on time, and can be accurate to min. If set to 24 hours, the switch can be accurate to seconds. In order to ensure the security of the system, the operation password can be set to manage the use of the transmitter on-line, to prevent the occurrence of human errors in operation, so that the transmitter can not work properly. In addition, the system can record the running time selectively. Finally, the system also has the function of fault detection and protection.
When the problem is detected, the decision of processing is made in time, and the relevant data is properly saved, which provides valuable reference for the subsequent fault diagnosis and treatment. The work flow of the microcontroller system in radio transmitter is as follows: the microcontroller handles the switches and digital signals transmitted by sensors and transmitters, compares them with the pre-set values after processing, and judges and obtains the current operation of the whole system according to the comparison results [3]. If there are no abnormalities in the comparison results, the corresponding operations can be done according to the current situation. If there are abnormalities in the comparison results, the normal operation can only be carried out after adjusting the data. The structure of the microcontroller system is shown in Figure 1. In the whole system, the microprocessor CPU is the core, which is responsible for the system data judgment and processing functions, and the issuance of control signals, and occupies the “brain” position in the coordinated movement of the system. The keyboard input module and the LCD display module belong to the man-machine interface module of the microcontroller system and undertake their respective functions and tasks. The remote monitoring and control module can expand the function of the system, complete keyboard operation, and realize remote control of the broadcasting transmitter. This kind of broadcasting transmitter can ensure the safety and normal operation of the whole system even if it is unattended, because of the cluster management of the system. Drive circuit design. LCD display is normal, first of all, it should be equipped with the corresponding driving circuit. At present, most LCD displays on the market are equipped with driver modules. However, the driver modules on LCD are generally expensive. In order to reduce the cost of system construction, it is necessary to design the driver module and use SED1335 as the core chip [4]. Selection of MCU. According to the characteristics of the broadcasting transmitter and the technical requirements of the system for the transmitter microcontroller, it can be concluded that the characteristics of the microcomputer control system include the following aspects: strong interference function, high-speed performance of the system and the need for a large number of I/O. In the system we designed, a simplified circuit design with multi-CPU is used. At the same time, the functions of the whole system are divided into different CPUs, and a variety of high-speed communication interfaces of AVR MCU can make the multi-machine structure simple and easy. In order to provide a stable reference voltage for A/D, 7805 three-terminal stabilizer is used to ensure the design. For example, LCD, I/O channel and remote communication interface devices are not introduced because of their simplicity.
Figure 2 shows the core structure of the 3/5KW controller. Software design of microcontroller. In the broadcasting microcontroller system, the control core is the controller, which is mainly responsible for the switch and state detection of the broadcasting transmitter. The stability of broadcasting microcontroller is directly related to the stability of broadcasting transmitter, and has a direct and important impact on the broadcasting quality of broadcasting station. In order to ensure software stability, we should start with software design and final code compilation: first, the rigorousness of the main framework of the program, compiling software according to the software compiling process, especially not allowing the process itself to have logical confusion and other defects; second, making scientific planning for system resource management to ensure the effectiveness and rational unification of resources, in embedded systems, resources in the system 10 If the resources in the system are not planned systematically, the system may be unstable under unexpected circumstances. Thirdly, because the parts of the program are independent of each other, modular design should be achieved. The system is not isolated, it is composed of many functions. So in order to ensure the stability of the system, we should combine all parts organically, so that the readability of the program can be increased, and the stability and reliability of the program can also be improved. Broadcasting transmitter is usually located in a relatively high terrain. For the managers of broadcasting transmitter, the management is more difficult, and due to long-term duty factors, it is easy to appear negligence. This will lead to a great relationship between the subjectivity of duty personnel and the quality of broadcasting. In this situation, the broadcast quality of radio transmitter can not be guaranteed.
After monitoring the broadcasting transmitter, it can not only reduce the workload of the staff, but also improve the broadcasting quality. Once the transmitter fails, it is an effective way to check the status of the transmitter through remote monitoring function, without the need for staff to go to the scene. When implementing remote control, there are two types of on-line mode, one is RS-485 on-line to the hub, thermostatic element the other is directly connected to the computer through 485 to 232 chips. In the latter connection mode, because each transmitter corresponds to a computer communication port, each transmitter can be monitored by multi-threaded programming, which prevents round trip, thus greatly improving the speed of remote communication. In the research and development process of broadcasting transmitter, because 3/5 and 10KW adopt the main control core structure, the application of lower computer software is different in the process of remote communication. If the 3/5KW controller is used, the communication software of the slave computer is realized as follows: in the communication process, the slave computer is always in the passive response state, and the interface used in the remote communication is usually USART interface, so the communication interface must be placed on the main CPU. In the process of communication, in order to reduce the time spent on the main CPU and the timely response time of the upper computer commands, the interrupt writing method should be substituted for the writing of communication programs. In the process of designing the program, the real-time requirement of the system should also be considered. If interrupt writing is adopted, the highest priority should be used. Initialize the serial port settings and related programming, respond to the interruption of serial communication reception, intercept the integrity of the received data frame according to the flag to judge whether to continue receiving the relevant data, and comprehensively analyze the received command of this communication. If it belongs to the switch command, it will be executed, otherwise it will not be executed, if the data is downloaded, it will be put into the corresponding area, if it is to upload data, it will be first. After putting the data into the communication buffer and closing the serial port to receive the interrupt, we can start sending the data, respond to the serial port to send the interrupt, and continue to execute the data sending command. We can judge the data transmission situation comprehensively. If the data transmission is not completed, we can continue sending. If the data transmission is completed, we can open the serial port to receive the interrupt. In the detection process, hardware is an important detection content. The hardware in the system mainly provides good conditions for software operation.
In the normal operation of the whole system, hardware is the carrier and the basis of reflecting the system function. Therefore, the transmitter control system center is the main control unit. So this requires the scientific and rational design of the main control unit. If the design of the main control unit is unreasonable, the actual performance and operation of the system may be greatly affected.
Microcontroller is an important part of FM radio transmitter. The normal operation of transmitter also needs the support of controller. It is an indispensable component. Therefore, before assembling and installing the broadcasting transmitter, it is necessary to test the software and hardware of the controller comprehensively to ensure the reliability and accuracy of the software and hardware of the controller [6]. Generally speaking, in the laboratory, the software and hardware of the detection controller may not be very grasped. For all-round detection of the software and hardware of the controller, it is necessary to install the controller on the broadcasting transmitter, and then carry out all-round detection. Because the working environment of broadcasting transmitter is relatively bad, it usually operates and works in the environment of high magnetic field, high radiation and high voltage, and the controller is an important part of the transmitter, so it is inevitable to be disturbed by external factors. Therefore, this requires the transmitter to have a strong anti-interference ability, which can operate normally in a certain interference. This requires debugging the microcontroller system of radio broadcasting transmitter to simulate the real environment, and after installation, testing and debugging in the field to ensure the stable operation of the microcontroller system. For radio transmitter micro-control system, microcontroller is an important monitoring device. Its use in the system reduces the difficulty and workload of staff, and is also an inevitable trend of the development of science and technology. At present, in the radio transmitter microcontroller system, microcontrollers are needed to provide services for the system.
Firstly, the paper analyses the technical requirements of the broadcasting transmitter for the microcontroller, and then analyses the system design from the aspects of LCD driver circuit design and FM controller hardware design.