User`s guide

Chapter 7 111
Reading/Writing Measurement Data
Retrieving Measurement Results
7. Reading/Writing Measurement Data
Retrieving Measurement Results
“Internal data arrays” on page 108 allow you to retrieve all measurement results
throughout a particular trace. Alternatively, markers allow you to retrieve measurement
results at your specified points. For information on how to retrieve marker values, refer to
“Retrieving Measurement Results at Marker Positions” on page 90.
Retrieving Internal Data Arrays
You can chose between the ASCII and binary data transfer formats when you retrieve
internal data arrays. For more information, refer to “Data Transfer Format” on page 104.
Example 7-1 and Example 7-2 show sample programs that demonstrate how to retrieve
formatted data arrays. The sample program in Example 7-1 uses the ASCII transfer format
while the sample in Example 7-2 uses the binary transfer format. You can find the source
files of these programs, named read_asc.htb and read_bin.htb, on the sample program disk.
Each of the sample programs holds the sweep on channel 1, then retrieves and displays the
stimulus array for channel 1 and the formatted data array for trace 1.
The program in Example 7-1 is described in detail below:
Line 50 Assigns a GPIB address to the I/O pass.
Lines 70 to 90 These lines set channel 1's active trace to trace 1 and hold the sweep.
Lines 100 to 110 These lines retrieve the number of points in channel 1 and stores that
number into the Nop variable.
Line 120 Resizes the Fdata and Freq arrays based on the value of the Nop
variable (the number of points).
Line 160 Sets the data transfer format to ASCII.
Lines 180 to 190 These lines retrieve the formatted data array for the active trace (trace
1) in channel 1, and store the data into the Fdata array.
Lines 200 to 210 These lines retrieve the stimulus array for channel 1 and stores the data
into the Freq variable.
Lines 250 to 260 These lines retrieve the data format for the active trace (trace 1) in
channel 1, and store it into the Fmt$ array.
Lines 270 to 400 The lines display each point along with one measured value and a
frequency if the Fmt$ is “MLOG”, “PHAS”, “GDEL”, “MLIN”,
“SWR”, “REAL”, “IMAG”, or “UPH”; or along with two measured
values and a frequency if Fmt$ returns any other string.