User`s guide

Table B-4c. SDF_DATA_HDR (Data Header record)
Field
Index
Binary
Index*
Field Name/Description
Data
Type
Range/
Units
11 43:44 xResolution_type — tells you how to find x-axis values for this
Data Header record’s traces.
0=linear — calculate values from abscissa_firstX and
abscissa_deltaX
1=logarithmic — calculate values from abscissa_firstX
and abscissa_deltaX
2=arbitrary, one per file — find values in the X-axis
Data record; same vector used for every trace in the
measurement file
3=arbitrary, one per data type — find values in the
X-axis Data record; same x-axis vector used for each
trace associated with this record
4=arbitrary, one per trace — find values in the X-axis
Data record; unique x-axis vector for each trace
associated with this record
short 0:4
12 45:46 xdata_type — tells you the size and format of each x-axis
value.
1=short (two-byte, binary-encoded integer)
2=long (four-byte, binary-encoded integer)
3=float (four-byte, binary floating-point number)
4=double (eight-byte, binary floating-point number)
This field is only valid if xResolution_type is 2, 3, or 4.
short 1:4
13 47:48 xPerPoint — number of x-axis values per each trace point.
This field is only valid if xResolution_type is 2, 3, or 4.
short 0:32767
14 49:50 ydata_type — tells you the size and format of each y-axis
value.
NOTE: If yIsComplex=1, both the real and imaginary
components of each y value require the number of bytes
specified here.
1=short (two-byte, binary-encoded integer)
2=long (four-byte, binary-encoded integer)
3=float (four-byte, binary floating-point number)
4=double (eight-byte, binary floating-point number)
short 1:4
15 51:52 yPerPoint — number of y-axis values per each trace
point.
NOTE: A value containing both real and imaginary
components is still considered a single value.
short 0:32767
16 53:54 yIsComplex
0=each y value has only a real component
1=each y value has both a real and an imaginary
component
short 0:1
17 55:56 yIsNormalized
0=not normalized
1=normalized (all y values fall between 0.0 and 1.0 and
are unitless, for example coherence or power spectrum).
short 0:1
18 57:58 yIsPowerData
0=not power data (for example, linear spectrum)
1=power data (for example, auto-power spectrum)
short 0:1
*Bytes i.d. = instrument-dependent
Standard Data Format (SDF)
B-15