SR-52 Simple Linear Filtering of Time Series Data

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An extract from Simple Linear Filtering of Time Series Data on a Programmable Calculator, Robert Franklin, Comput. Biol. Med., Vol. 12, No. 2, pp. 175-178, 1982

Abstract-A program is presented for the Texas Instruments SR-52 calculator which calculates moving averages of time series data. In addition to providing averages the programs also keeps track of which data item in a sequence to enter next.
INTRODUCTION
A running or moving average is a relatively simple way to smooth time-ordered data. The calculations are sufficiently tedious, however, that doing them on a hand calculator represents a substantial investment of time. For any set of data elements the number ofvalues to be entered on a calculator, by hand, for a moving average is S[ 1 + (N - S)] where S is the span or number of data elements per each averaging operation and N is the total number of data elements. A moving average of span 3 on a set of 50 data elements requires entering 144 numbers. The program presented here significantly reduces the work involved in these calculations. By internally reordering the data the program requires that the user enter each data element once.
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SUMMARY
A program is presented for the Texas Instruments SR-52 programmable calculator which computes simple moving averages of time series data. Design and programming emphasis was placed on ease of use and time savings. The output from this program is useful in determining the shape of time-ordered sequences of data. The technique used for internally reordering the data after each individual calculation is explained is some detail as it may be useful in any program of an algorithm involving a moving window on a sequence of data.

Besides the introduction, the algorithm, program description, sample run (w/ tables of register usage, program procedure & listing), summary (w/ charts & example run) & references.

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