/*****************************************************************************
*                                                                            *
*   STARMS.SPL  Copyright (C) 2000 DSP Development Corporation               *
*                               All Rights Reserved                          *
*                                                                            *
*   Author:      Randy Race                                                  *
*                                                                            *
*   Synopsis:    Calculates the short time averaged RMS series               *
*                                                                            *
*   Revisions:    3 Apr 2000  RRR  Creation                                  *
*                                                                            *
*****************************************************************************/

#if @HELP_STARMS

    STARMS

    Purpose: Calculates the short time averaged RMS series

    Syntax:  STARMS(s, interval)

                     s -  input series

              interval - an optional integer, duration of each RMS segment,
                         defaults to 1.0 second

    Returns: A series, the short time averaged RMS series


    Example:
             W1: gsin(1000, .01, 1)
             W2: starms(w1)

             W2 consists of a 10 point series where each point has a
             value of 0.707107, the RMS value of each 1 second segment
             of W1.

    Example:
             W4: starms(w1, 0.1)

             W4 consists of a 10 point series where the values now vary
             since the RMS value of W1 varies over a 0.1 second interval.

    Remarks:
             The number of segments used to calculate the RMS value is

                     segsize = int(interval / deltax(s))

              where s is the input series.

              The segments are non-overlapping.


    See Also:
             Colmean
             RMS
#endif


/* short time averaged RMS series */
starms(s, interval)
{
        local segsize;

        if (argc < 2)
        {
                if (argc < 1) error("starms - input series required");

                interval = 1;
        }

        /* number of points per segment */
        segsize = int(interval / deltax(s));

        /* divide into segments */
        s = ravel(s, segsize);

        /* calculate rms on each column and transpose to get single series */
        s = transpose(sqrt(colmean(s * s)));

        return(s);
}