R&S SGT100A, User Manual

Page: 213 / 593

Signal Generator Settings
R&S
®
SGT100A
182 User Manual 1176.8674.02 ─ 07
Shaping Table
In the R&S SGT, there are two ways to define the predistortion function in form of a
shaping table:
●
Externally
Create a correction table file as a CSV file with Microsoft Excel, with a Notepad or
a similar tool, save it with the predefined extension, transfer it to and load it into the
instrument.
See also
"File format of the correction table file" on page 182.
●
Internally
Use the built-in editor table editor, see Chapter 7.6.3.3, "Edit Predistortion Table
Settings" , on page 191.
File format of the correction table file
The correction table files are files with predefined extension and simple file format, see
Table 7-12 .
Table 7-12: Shaping table files: format and extensions
Predistortion model File extension Header (optional)
AM/AM *.dpd_magn # Rohde & Schwarz - Digital AM/AM
Predistortion
Table Pin[dBm],deltaPower[dB]
AM/PM
*.dpd_phase # Rohde & Schwarz - Digital AM/PM
Predistortion
Table Pin[dBm],deltaPhase[deg]x
The header is optional. The file content is a list of up to 4000 comma-separated value
pairs, describing the delta values for amplitude or phase related to the absolute input
power P
in
; a new line indicator separates the pairs.
For values above the selected Input Range (PEP
in
) , the predistortion function assumes
a linear ratio of the input to output power.
Example: Shaping table file content (*.dpd_magn file)
# Rohde & Schwarz - Digital AM/AM Predistortion Table
Pin[dBm],deltaPower[dBm]
-30,0.5
3,-0.01
Normalized Data
In the R&S SGT, there are two ways to define the predistortion function as normalized
data:
●
Externally
We recommend that you calculate the normalized correction data by a connected
R&S
®
FSW equipped with R&S
®
FSW-K18 Power Amplifier and Envelope Tracking
Measurements option.
You can also create the correction table file as a CSV file with Microsoft Excel, with
a Notepad or a similar tool, save it with the predefined extension, transfer it to and
load it into the instrument.
Applying Digital Predistortion