The Complete Fast Fourier Transform and Cascaded Transition-Band Filters to Reduce the Noise of Deconvolution

Patterson, P.E.

Sandia National Laboratories

关键词: Signal-To-Noise Ratio;    Transients;    Wave Forms;    Electromagnetic Filters;    Data Acquisition Systems;   

DOI  :  10.2172/776348
RP-ID  :  SAND2000-1310
RP-ID  :  AC04-94AL85000
RP-ID  :  776348

美国|英语

来源: UNT Digital Library

【 摘 要 】

A measurement system's components: cabling, delay line, waveform recorder, etc., degrade acquired signals and their respective bandlimited frequency responses. Compensation software corrects for this frequency-dependent spectral degradation by deconvolving the transfer function of the entire measurement system out of the measured signal spectra. This report describes methods to transfer the characteristics of a wide bandwidth repetitive sampling oscilloscope to a single-shot transient digitizer, characterize the measurement system, develop a cascaded transition-band filter, and compensate data acquired with the filtered, characterized measurement system. These procedures are easily implemented, execute quickly, and successfully compensate waveforms possessing endpoint discontinuities. Waveforms possessing endpoint discontinuities are made to appear duration-limited and continuous. The spectra for these modified waveforms are correct, including at dc. The deconvolution process introduces unavoidable noise. Filtering is applied to reduce the deconvolution noise while minimally affecting compensated waveform risetime and amplitude. Resultant compensated data retains its initial dc baseline offset with improved waveform fidelity and low noise of deconvolution.