DELTAX

Purpose:

Returns the delta x increment of a series or table, i.e. the inverse of the sample rate.

Syntax:

DELTAX(series)

series

-

Optional. A series or table. Defaults to the current Window.

Returns:

A scalar.

Example:

deltax(gsin(20,.05))

 

returns 0.05, the inverse of the sampling rate.

Example:

W1: gnorm(1000, 1/1000)

W2: gnorm(length(w1), deltax(w1))

 

W2 contains a random series with the same length and deltax as W1.

Remarks:

When referencing a table, DELTAX returns the delta x increment of the first column in the table.

 

Many series have X values that are monotonically rising by a constant X increment such that:

 

image\xy01.gif

 

A series with X values of this form is referred to as an interval series. Because any X value from an interval series can be computed with:

 

image\XY02.gif

 

an interval series requires only the DELTAX and XOFFSET values to determine the X values. Thus, for an interval series, explicit X values are not necessary, decreasing the data storage requirements by a factor of 2. Also, because the X values for an interval series are regularly monotonic, speed optimizations for plotting and computations are available.

 

See XY to create a series with irregularly spaced X values.

See Also:

DELTAY

RATE

SETDELTAX

SETDELTAY

SETXOFFSET

SETYOFFSET

XOFFSET

YOFFSET