Research On Correction Methods Of Digital In Wide-band Oscilloscope

Wide-band oscilloscope has developed for decades as a necessary measuring and testing tool for electrical engineers. Its performance index has reached high level.With the continuously improvement of the oscilloscope analog bandwidth and sampling rate,Some errors and noise in the wide-band oscilloscope,have restricted measurement accuracy of the wide-band oscilloscope. How to correct this errors becomes an urgent problem for the wide-band oscilloscope design developers. This thesis adopts the ideas and methods of the digital signal processing technology to correct the errors in wide-band oscilloscope. It can give full play to the excellent characteristics of digital signal processing, and has important significance for improving quality of waveform display and measurement accuracy.This thesis’ s main contents are as follows:1. The conditions are given for applying digital filter in the wide-band oscilloscope.Wide-band oscilloscope is a typical distortionless transmission system, so the digital filter used in the wide-band oscilloscope must be a distortionless transmission system too. In addition, the influence of digital filter in overshoot and rise time should be considered.2. The magnitude frequency response error in analog channel of wide-band oscilloscope is analyzed and the method to correct this error is researched. Firstly, the reasons for analog channel magnitude frequency response error is analyzed.Then, the FIR filter to correct this error using the method of compensation is designed.3. The error in time-interleaved nonuniform sampling is analyzed and the method to correct this error is researched,at the basis,the conclusion that the noise is relatively concentrated is found,and a CIC structure digital filter to correct it is designed.4. The error in clock jitter sampling is analyzed sampling and the method to correct this error is researched.Firstly, the impact of this error on sampling system is analyzed,and the spectrum of input signal is relatively concentrated in random equivalent sampling oscilloscope,then the FIR filter with multi- passband to correct this error is designed.5. Functional verification and performance testing. through the actual engineering application, the correction methods can better to complete the calibration requirements.