Agilent Technologies 3588A Betriebsanweisung PDF herunterladen (Seite 214)

You can calculate X-axis values this way when xResolution_type is 1 (logarithmic resolution):

x0 = abscissa_firstX

x1 = x0 * abscissa_deltaX

x2 = x0 * abscissa_deltaX

x3 = x0 * abscissa_deltaX

xn = x0 * abscissa_deltaX

(where n = num_of_points −1)

When consecutive trace points are not evenly spaced along the X-axis (xResolution_type = 2, 3, or 4), the

SDF file includes an X-axis Data record. And when the file defines a single trace, that record includes

just one vector of X-axis values.

Three fields in the Data Header record tell you how to read X-axis values from the X-axis

Data record:

num_of_points: tells you how many discrete points the trace is composed of.

xdata_type: tells you the size and format of each X-axis value. (This information is encoded.

For example, if xdata_type = 3, the size is four bytes and the format is binary

floating-point.)

xPerPoint: tells you how many X-axis values are used to define a single point.

You can determine the size (in bytes) of the X-axis Data record’s data block with the

following formula:

num_of_points * xPerPoint * Size

The value of “Size” is encoded in xdata_type, as shown below:

xdata_type Size (bytes)

2,3 4

Standard Data Format (SDF)

B-28

1 2 ... 209 210 211 212 213 214 215 216 217 218 219 ... 253 254

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Agilent Technologies 3588A Betriebsanweisung Seite 214