Dissertation > Industrial Technology > Radio electronics, telecommunications technology > Communicate > Communication theory > Signal processing > Image signal processing

Research of Signal Distortion Compensation Algorithm in Audio/Video Device’s Assessment System

Author WangHongLing
Tutor MenAiDong
School Beijing University of Posts and Telecommunications
Course Communication and Information System
Keywords Video Reviews Signal acquisition Quantization error Distortion compensation Filter Design
CLC TN911.73
Type Master's thesis
Year 2011
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With the rapid development of high-tech , applicable to different areas of colored modern digital the endless video equipment ; , high quality requirements for broadcast TV system is becoming more and more due to the increase in demand for media information . Therefore , the research and development of video equipment compatibility and certification testing , quality inspection , automatic production and testing as well as the open-circuit video system test requires a sophisticated , reliable , convenient , quick video test system . Based on the evaluation of the needs of the modern video equipment , in accordance with international standards and national standards , designed to achieve a set of automatic remote control audio and video measuring system , in order to achieve a comprehensive test of the indicators of the video component of the output of the device under test . The evaluation system is composed by a test signal generator and signal evaluation end . In order to achieve compatibility and convenience of the system , this article uses HD acquisition equipment test signal acquisition in the evaluation of end . Meanwhile, in order to improve the accuracy and stability of the system evaluation , research HD acquisition equipment acquisition principle , analysis of the distortion caused by the quantization error of the acquisition process , and sampling format , take the offset method . In order to eliminate the quantization error , there is proposed adding a ramp signal , the dither signal , and taking the mean of the method ; decline in accuracy caused by the test to eliminate sampling consistent approximation to achieve the desired design FIR filter interpolation sampling . Also studied the overshoot and undershoot distortion , the band-limiting distortion inherent performance of the system such as group delay distortion caused distortion , in order to offset the ideal characteristics of the system itself , the corresponding filtering equalization method - using frequency domain equalization The method eliminates overshoot and undershoot of distortion , the phases are combined with a window function Heng reduce bandlimited distortion IIR all-pass filter , phase compensation to eliminate the group delay distortion . After specific steps of the compensation , the accuracy of the system evaluation results has been greatly improved and reliable test results .

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