2. The problems of radio and television solid-state transmitters and maintenance strategies
Compared with traditional transmission methods, solid-state radio and television transmitters can achieve the goal of high-efficiency and stable transmission of information, and the investment cost of the entire technical system is relatively low. At present, it is the main technical form used in the development of radio and television in my country, and it is closely related to the quality of its programs. . The technology will also have some failures in the actual operation process, therefore, it is necessary to adopt corresponding maintenance strategies, as follows:
(1) The output power is too low
Radio and television solid-state transmitters can comprehensively process voltage, and can continuously adjust the regional signal transmission structure based on the basic principle of local program control. Based on this, once there is a change in the signal transmission structure between the solid-state transmitter and an external structure, the power output by the exciter will also change at this time; however, if there is no shift in the regulator, then it can be clear The output power of the radio and television solid-state transmitter is relatively low, and the system has no way to effectively adjust the intensity of signal transmission at this time.
Regarding the problem of too low output power, broadcast and television maintenance personnel need to start with the overall structure to check the actual situation of the transmission power; if the output structure is touched in the normal state, and the transmission power does not change, At this point, it is clear that there should be no major problems with the transmission structure, and only need to locally adjust the transmission power of the solid-state transmitter to recover.
The specific technical points for handling local implementation issues are as follows:
First, first, power detection can be performed, that is, the power detection of the signal conversion devices on various lines output from the solid-state transmitter, and comparison with the standard value, can further clarify the fault problem. Second, the resistance of the test part of the power transmission route can be further checked locally, and the actual power transmission conditions of the abnormal part can be recorded. Third, replace the components with excessive input power of the exciter, and then connect the relevant programs and restart them to complete the repair.
(2) The output power is zero
The normal transmission power of the signal is 550W, relying on the automatic control unit, the transmission power can be adjusted independently. Based on this, it is clear that during the transmission process, as long as the overall signal strength of the unit structure is continuously maintained at 550W. From a practical point of view, in the process of signal transmission, because the signal status of the local circuit components is not good, or the RF data input and output are abnormal, then this means that the entire data power cannot maintain the standard status, and the equipment The input and output power of the device will be displayed as zero.
First, when repairing this type of fault, it is necessary to start with a comprehensive analysis of the impedance converter at the input end. If the resistance of the impedance converter is relatively large, then the internal transmission voltage and current value of the unit will gradually decrease at this time. Considering that the radio and television solid-state transmitter has the characteristics of phased signal transmission, the power of the final signal communication process will become zero. In this regard, the resistance of the impedance converter can be adjusted so that the transmission power can be restored. Second, when solving the radio frequency problem, because the radio frequency control circuit of the solid-state transmitter is unreasonably connected, the power is zero. In this regard, the maintenance personnel can first check the lines around the transmitter. If this does not solve the problem, then they need to continue to check the lines one by one, and then identify the short-circuit part and replace it. Third, after completing the replacement of the circuit components, conduct a comprehensive test on the impedance module of the circuit part, mainly to observe whether there is rejection. If under the re-adjusted impedance power, part of the line cannot operate normally, then it is necessary to analyze the rejection problem in depth. Repair the fault based on the above steps to effectively solve the problem.
(3) Abnormal methods and procedures
Abnormalities in the signal transmission process are one of the more common problems. The specific manifestations are: during the transmission process, the phased signals are intermittent, or the signal recognition level is very low. In response to this type of problem, relevant maintenance personnel need to test external components. If the inductive strength of the solid-state transmitter is found to be insufficient, or there is obvious external damage, it means that there is already a problem with the program. In the process of adjusting the signal, it is recommended to adopt a local adjustment method for hardware problems, for example, for the initial signal, and then adjust the intensity, which can be adjusted from "larger" to "centered"; at the same time, the signal transmission time is carried out The adjustment can be specifically adjusted from "30 minutes" to "45 minutes". Relying on the way of extending the signal transmission time, the signal transmission strength can be reduced. This method can effectively detect whether the external components are abnormal.
Simply put, it is to reduce the loss ratio of the solid-state transmitter signal in the external component transmission, and the biggest advantage of this method is that it can fully comply with the actual needs of signal transmission, so as to deal with abnormal problems in a targeted manner. At the same time, in order to effectively solve the problem of program abnormality, rely on the internal signal control mode, and then comprehensively analyze whether the phased signal transmission is stable. In terms of signal problems, for example, insufficient transmission strength, incomplete transmission signal, and so on. In this regard, the relevant maintenance personnel should rely on analog signals, and then deal with various problems in the transmission method. First, rely on the signal simulation processing model to detect the signal transmission channel to determine whether it is complete. Second, set the signal fuzzy processing program. With the support of this program, if the internal program receives an external signal and there is insufficient stability, then a "partial compensation" method can be implemented in the process of multiple signal conversions of the solid-state transmitter, so as to solve the problem. Procedural issues.
(4) Failure of the power supply link
In the process of signal transmission by the solid-state transmitter, it is very common for the power supply link to fail. Generally speaking, if the power supply link fails, the operating power of the solid-state transmitter will not be stable enough, for example, it will be fast and slow, and the surrounding cable transmission system may be damaged. Regarding the failure of the power supply link, the suggested repairable strategy can start from these aspects: First, it is necessary to comprehensively detect whether the power supply in the entire signal transmission structure is tightly connected. For example, check whether the power plug is improperly connected; check whether the local power plug has any disclosure; check whether the power plug has poor contact, and so on. Second, after powering off the solid-state transmitter, check all power supply lines to make sure that the surrounding lines remain smooth. If the power transmission line of the solid-state transmitter has problems such as line cross interference, the problem can be solved through timely sorting. Third, comprehensively detect whether the cable connection around the solid-state transmitter is smooth. For example, if there is a high interference signal around a cable line buried underground, the solid-state transmitter signal will be locally damaged. Therefore, it can be resolved through inspection and related measures.
(5) Inaccurate parameter values
In the actual operation of the solid-state transmitter, when judging the signal stability, it is necessary to rely on the analysis of the parameters of the radio frequency structure, the power supply control structure, the signal unity amplification program, the cold air system and so on. However, from a practical point of view, in the process of signal transmission of solid-state transmitters, it is very likely that there is a problem that the local circuit does not adapt to each part of the signal, which is a problem often mentioned by daily maintenance personnel, namely: in the communication link The parameter value is not accurate enough.
To solve this kind of problems, the solution requires maintenance personnel, not only need to comprehensively control the transmission link of the solid-state transmitter, but also need to pay attention to the processing of daily equipment and frequency modulation, that is, it is necessary to mark the parameters of each part of the solid-state transmitter. In the process of daily signal transmission of solid-state transmitters, there is usually a situation of integrated signal interference. For this type of problem, you can rely on the preliminary determination of the phased signal wave of the solid-state transmitter, and then repair the problem. For example, the signal strength is 115Hz/min. In the process of continuous monitoring of the signal strength, the maintenance personnel found that the system will have an abnormal parameter after 2-3 hours of transmission, which is lower than the standard value. parameter. In this regard, maintenance personnel or program management personnel adjust the signal parameters and repeatedly process the interference processing recovery of signal transmission, so that the parameter problem can be effectively solved and a valuable basis for subsequent maintenance can be provided.
3. Conclusion
To sum up, based on the principle of solid-state transmitters for broadcasting and television, this article discusses the problems and maintenance strategies of solid-state transmitters, hoping to further clarify the key points of technical application, and promote the maintenance measures to be more complete and mature, thereby ensuring broadcasting The quality of TV programs promotes the healthy development of the radio and television industry.
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