**
Abstract. **
Experimental
data processing often requires
to calculate the value of the signal is measured points – to interpolate
measured data. This is useful, for example, to analyze the experimental data,
the graphical representation of the results obtained, calculating signal
characteristics. Interpolation is almost always accompanied by errors, the
knowledge of which can be used to select the interpolation method, the
subsequent measurement planning, determining the coordinates measured at the
same points.

Typically, a priori information for constructing functional
data model is insufficient. Or to build a functional
model is fundamentally impossible. Therefore, using standard techniques of
interpolation error estimation is very difficult. The task of
interpolation of an arbitrary function is not the purpose of our work. The aim
of this work is to demonstrate the capabilities of a simple method for
estimating the error of interpolation of the experimental data to select the
interpolation method, the coordinates of the measuring points, the analysis of
the measured data.

The proposed method is based on the following idea. Let the
measured values at the points well enough describe the properties of the
signal. In order to evaluate the interpolation error, we will evaluate the
difference in values between the two interpolations consistently held, with the
second interpolation uses as a nodal point values from the first interpolation.

This work describes the use of a simple method of
interpolation error estimate. This method does not require formal study the
properties of the interpolated signal and has no obvious limitations when using
any interpolation method. The natural limitation of this method is the
requirement of such a measurement step that provides an adequate description of
the properties of the test signal.

**
Key words: **interpolation, error
estimation.

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