The Reliability Improvement And Status Monitoring Technologies For The DMB Terminal

Due to the advantages of wide coverage,unlimited number of terminals and business diversity,Digital Media Broadcasting(DMB)has been recently widely used in education information releasing,early warning of disasters,and the information publication of the scenic spot.These applications usually need many DMB receivers to drive LED or LCD screens to display multimedia information.But the electromagnetic radiations from the LED/LCD screen will disturb the DMB receiver connected to it,and significantly reduced the receiving sensitivity.Also the administrator of the DMB system needs a monitoring system in which the statuses of all the DMB terminals can be displayed friendly.This paper aims to solve the above problems.The paper studies and proposes several methods to improve the anti-interference ability of the DMB receives and monitor their status.The results of the research will improve the reliability of the DMB receiver under complicated electromagnetic environment,and reduce the maintenance workload of the DMB system,and consequently,promote the popularity of the DMB technology.In DMB terminal anti-interference technology research,experiments were carried out to find the regulation of the effect on the DMB receiver caused by the electromagnetic radiation from LED and LCD screens.Based on the experiment results,a narrowband LC band-pass filter is designed to reduce the interference of the noise signals out of band.A communication bridging method using low-cost WiFi module is then proposed,to avoid the direct connection between the DMB receiver and the LCD/LED screen and enlarge their distance to reduce the noise power fed to the DMB receiver.In terminal status monitoring system development,considering that the status information data is small and updating period is not necessarily high,a low-profile and low-cost WiFi module is integrated in the DMB receiver to enable it send the status through the local area network.Monitoring software is developed to collect the status data and display them.The software is installed on the computer in the monitoring center,so the administrator can remotely know the working status of the DMB system.The proposed methods are tested in the campus DMB system in Chongqing University of Post and Telecommunications,where there are many public LCD panels in each teaching building and each dormitory building,and DMB speakers in each classroom.The results showed that the anti-interference methods can improve thesensitivity of the DMB wireless LED/LCD screens about 4-9 dB,compared to the terminals without processing.The status monitor system works stable to the DMB speakers in the classroom and enables the administrator to watch the bit error rate,volume and other information of each speaker at the monitoring center.This has significantly reduced the workload of the DMB system maintenance and management.