R&S SGT100A, Руководство пользователя

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Signal Generator Settings
R&S
®
SGT100A
150 User Manual 1176.8674.02 ─ 07
●
d is the Detroughing Factor (d) , that limit the supply voltage V
cc
in the low-power
region and controls the shaping.
The detroughing factor (d) can be set manually or derived from the selected V
cc
value. In the latter case, it is calculated as follows:
d = V
cc,min
/V
cc,max
See Couple Detroughing Factor with Vcc .
A "Detroughing Factor = 0" defines a linear function.
See also "Converting Shaping Functions and Understanding the Displayed Values"
on page 152.
About the Polynomial Function
The polynomial function is an analytical method to describe a shaping function. The
polynomial function is defined as follows:
f(x) = a
0
+
∑
(a
n
*x
n
), where n
≤
10 and:
●
Depending on the "Envelope Voltage Adaptation" mode, f(x) is:
– f(x) = V
cc
(x) in "Auto Power"
– f(x) = V
cc
/V
cc,max
(x) in "Auto Normalized/Manual"
●
The polynomial order n , the polynomial constant a
0
, and polynomial coefficients a
0
to a
n
are user-definable, see Chapter 7.5.7, "Polynomial Coefficients Setting" ,
on page 176
●
x depends on the "Envelope Voltage Adaptation" mode, see Table 7-6
The default polynomial function with n = 1, a
0
= 0 and a
0
= 1 describes a linear func-
tion.
See also
●
Figure 7-20
●
"Converting Shaping Functions and Understanding the Displayed Values"
on page 152.
File format of the polynomial function file
You can store a polynomial function in a file or even define the polynomial coefficients,
store them as a file and load this file into the instrument. The polynomial files are files
with extension
*.iq_poly
.
The file contains an optional header
# Rohde & Schwarz - IQ Output
Envelope Polynomial Coefficients # a0,a1,a2,...
and a list of comma-
separated coefficient values.
Example: Polynomial function file content
# Rohde & Schwarz - IQ Output Envelope Shaping Table
# a0,a1,a2,...
0.135,0.91,0.34,-0.59,-0.11
Generation of Envelope Tracking Signals