The Research Of The Key Points In Frequency Band Extension Of Digital System

In this paper, the extension theory of bandwidth in digital system and three key points of frequency band extension technology are studied experimentally by simulation.The first point we analyzed is the digital deconvolution with noise. We discussed common methods of digital deconvolution and analyzed effects of noise on it. Then, we simulated digital deconvolution filters and optimization criteria of filtration parameters. After that, we gave the application of them in the frequency band extension technique.The second point is the compensation of time base distortion and drift. First, we analyzed time base distortion and its effects on signal measurement. Then we compared different methods of measuring the time base distortion and simulated the analytic signal method. After that, we discussed the compensation methods of time base distortion. The time base drift deduced by the change of temperature is discussed particularly and the compensation method of it is analyzed. Finally, we also studied frequency band extension under time base distortion condition by simulation. The results show that the compensation of time base distortion can reduce the error of signal and then increase the accuracy of frequency band extension.The third is the compensation of time base jitter. We summarized the effects of time base jitter and the methods to measure the time base jitter. Different methods for time base jitter compensating are analyzed and simulated. On the base of that a new method called improved probability density function method is developed to compensate time base jitter. The frequency band extension with time base jitter is also studied by simulation. The results show that the compensation of time jitter can reduce the error of signal and then increase the accuracy of frequency band extension.We summarized three key points of frequency band extension technology and systematic studied these points by simulation. An experiment executing frequency band extension for a concrete digital measurement system was performed. The results show that the frequency band extension technology using digital deconvolution has feasibility.