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Digital Television DVB signal detection and prevention of illegal methods

Level is set to 45dBm, C / N is set to 8dB, verify no one is disturbed, may not be verified equipment malfunction. ② the main transmitter output level is set to ~ 55dBm, C / N is set to l0dB, constantly under the conditions of the main transmitter to the fluctuation range of 4dB to plus or minus 2dB / second wave conditions change the main transmitter output ping, verify that no one is disturbed, may not be verified equipment malfunction. ③ the main transmitter output level is set to 55dBm, C / N is set to l0dB, constantly under the conditions of the main transmitter is plus or minus 5dB step increase / decrease the output level of the main transmitter, verify no one is interference , proven equipment shall not malfunction. ④ stream generator 1 will take eight off standby transmitter, the main transmitter output level is set to 55dBIT /, C / N is set to 10dB, the main transmitter through switch the input from 1 to 2 may not cut malfunction. ⑤ the flow generator l access code, disconnect the spare transmitter, the transmitter will be the primary backup transmitter output level is set to 55dBm, C / N is set to 10dB, the first access to the main transmitter, cutting through the switch to the standby transmitter device shall be verified malfunction. 2Ts how to prevent the illegal flow signal monitoring platform for attacks on the security monitoring devices, stream analysis through predictive monitoring of alarm signals must be taken to prevent illegal means, the delay comparison is to ensure the reliability of broadcast, broadcast equipment pad is broadcast and necessary emergency measures. Detection Method: In the normal signal coverage of the illegal signal to start, because the structure TS transport stream encoding, multiplexing structure, the form parameter, the name will mutate, digital satellite receivers in the demultiplexing and decoding discontinuity occurs when decoding, decoding buffer overflow, de-multiplexing and decoding of various parameters such as internal re-initialization process,[link widoczny dla zalogowanych], the corresponding video and audio signals output a short time the mosaic, the picture static frame, the screen black (Note that not signal an interrupt, because the digital satellite receiver there is always the output of the video signal sync), or sudden loss of sound phenomena such a short time. Described in the previous section, illegal signals in the RF stage of testing in different ways, the monitoring platform to monitor 26 through the Information Technology SCIENCE & 1 Ⅲ ECHNOLOOYINFORMAlION stream error state to determine whether illegal signals attack. Including the table structure changes, ETR290 errors, bandwidth changes,[link widoczny dla zalogowanych], including counting discrete, TS streaming content characteristics change. Therefore, the normal signal coverage in the illegal start of stream monitoring equipment to detect mutations in a large number of Ts flow error, if it reaches the set threshold, combined with static frame, black, lost, and analog audio monitoring, can believe that an illegal intrusion alarm signal. Broadcast delay: measured according to various indicators of instruments to determine only that the image of the objective performance. However, the legitimacy of the image does not show it. Therefore, the traditional video monitoring subjective count even in the increasingly sophisticated monitoring is still needed today. Experiments have been done, attendant back Shí television image, suddenly turned in the shortest time to determine the legality of the received image: Logo judged according to the time required is less than 1 second, but according to the image content to determine at least 5 seconds or more. According to the requirements of SARFT, should the illegal signals occurred attacks in one second to respond quickly. Alone to determine if artificial, obviously can not meet the requirements. But if it is broadcast in the case of delay, then to the room managers ample reaction time. Wei delay the broadcast, that is, the satellite signal between the receiver and the broadcasting side to set first in first out buffer, out to the local network broadcast some time before the TS stream to stream. Assuming the delay time is thirty seconds,[link widoczny dla zalogowanych], if the signal is now illegal invasion took place, the user is still normal to see the current program, there are three officers on duty a second time to a program stream switching and other operations, so the reaction time significantly increase, reducing the burden of duty. Alternate program stream: Yue invasion illegal signals occurred, how to deal with. As a satellite uplink stations, we can take a proactive approach to prevent,[link widoczny dla zalogowanych], increase the transmit power into the other. As a local television station and the downlink can cut to the alternate program source,[link widoczny dla zalogowanych], combining TS stream monitoring, delay broadcast technology, can effectively prevent the illegal signals broadcast to the user, resulting in greater losses.