EQUIVALENT-TIME SAMPLING AND REAL-TIME DIGITAL OSCILLOGRAPHY INTERPOLATION
V. N. Vyukhin
Institute of Automation and Electrometry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, E-mail: vvn@iae.nsk.su
Pages: 228-231
Abstract
Two methods for increasing the sampling rate in digital oscilloscopes are analyzed. The equivalent-time sampling is carried out via measuring and accumulating a series of oscillograms with a random phase and leads to nonuniform sampling. As a result, for few accumulations, the output noise level increases and the effective number of bits decreases. Interpolation in digital oscilloscopes is performed by sinx/x functions and its errors are determined by the length of the interpolating FIR filter. A table for choosing the filter length, depending on the interpolation coefficient and the normalized band of the reconstruction filter is presented. Obtaining a high interpolation coefficient requires considerable computational power.
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