Annotation:
The effectiveness of the operation of digital control systems, traffi c safety and
diagnostics depends to a large extent on the accuracy of the analog-to-digital conversion.
Methodical errors of the quantization transformation, time sampling and
the method of restoration of the input signal. This article is devoted to the analysis of the infl uence of sampling and storage devices of voltage-code converters on the
accuracy of analog-to-digital conversion. Models of transformation with instantaneous
counts and taking into account sampling and storage devices are considered,
errors of transformation of random stationary analog signals for these models are
determined. The difference in error estimates for models with instantaneous readings
and sample-and-hold circuits (SHC) makes it possible to determine the infl uence
of SHC on the accuracy of the conversion. Taking into account that to increase
noise immunity of the conversion, averaging of a given number of digital samples
within the step of time sampling and tracking digital averaging is used, the corresponding
expressions for estimating errors on models taking into account digital
averaging at instantaneous counts and taking into account sampling and storage
devices are obtained. An estimate has been introduced that allows one to determine
the effect of sampling and storage devices on the conversion error. A methodology
for calculating this estimate has been developed. Examples of the transformation
of a random signal with a constant spectral power density in the frequency band
from 0 to ? max and with a power spectral density decreasing with increasing
frequency are given. A technique has been developed that allows analyzing the
effect of sampling and storage devices on the analog-to-digital conversion error
of various stationary random signals.
Key words:
analog-to-digital conversion; sample-and-hold circuit; conversion error; stationary functions; root-mean-square error; digital methods for averaging samples; method of accuracy assessment