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At the conclusion of the overall conversion of digital cable TV, in the actual maintenance process, the digital signal is a discrete signal, the standard measure of the quality values can only terminal signal (or state) to evaluate the correctness of judgments, the line troubleshooting inconvenient. With the cable network from the one-way upgrade to the two-way network, EOC is widely deployed central office all the key nodes in the line (light machine or amplifier), the use of already deployed central office and the EOC EOC communications terminals, the use of SNMP protocol to obtain the line index, troubleshooting points.In the field of cable television, after the analog TV to digital TV conversion, the overall conversion lines facing network optimization, and the original measure of analog television to digital signals has been unable to determine the advantages and disadvantages. Currently the main cable line maintenance measuring instruments, according to the different nature of applications and are divided into two categories, one is high-end laboratory equipment-spectrum analyzer, spectrum changes observed in real time, expensive; other is commonly used in portable devices, commonly known as Digital Strength Meter, to measure the digital level, MER, BER, Constellation, the price moderate. Line maintenance and more with the current number of Strength Meter.But in the actual maintenance process, the digital signal is the average power level, MER, BER are statistics, circuit troubleshooting in real time, in particular, need to make a decision on the point of failure, the use of inconvenient lines need to be more user-friendly investigation and investigation tools.This practical application, using C++Builder programming, the use of open snmp+ +management agreement with the OFDM terminal device useful for data exchange; of the OFDM modulation working principle and technical characteristics of the analysis of the OFDM RF modulation parameters, through the acquisition the underlying data, realize the strength of signal noise, signal noise spectrum, traffic monitoring, and topology changes and other functions, to strengthen the basis of line investigation.This is the core of OFDM data collection terminal equipment, processing and display, using the line index data for the actual investigation and fault lines, experimental results show that the proposed scheme can use the conventional digital measuring instrument, difficult to find fault Strength Meter achieved the desired results.Inadequacy of this signal is observed in real time there are to be strengthened, the other did not encrypt network traffic, without considering security management, this is where the next step needs to be improved.
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