SAMPLE AUTO-RANGING DATA ACQUISITION USING NATIONAL INSTRUMENTS SUPPORT

Cristian Zet, Marinel Temneanu, Cristian Fosalau, Mihai Cretu

Abstract

In the process of data acquisition the analogic gain is usually determined by the peak value of the input signal. For all samples the quantization error is theoretically less than 1/2 LSB. However for samples having small value, the relative error due to the quantization is high, and it goes higher with the decreasing of the sample value. The relative measuring error can be reduced by dynamically setting the proper gain. This is usually achieved with a supplementary hardware arrangement. The solution proposed in this paper consists in a numeric algorithm, developed in LabView, which replaces the hardware. The idea is to measure the same signal with many channels, set up with different gains, and to rebuild the signals, choosing the samples measured with the maximum accuracy. Sample translation must be performed due to the inter-channel delay.

Keywords

data acquisition, sample, quantization error

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IMEKO-TC4-2001-141.pdf

DOI

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IMEKO TC

TC4 - Measurement of Electrical Quantities

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