R&S SGT100A, Руководство пользователя

Страница: 180 / 593

Signal Generator Settings
R&S
®
SGT100A
149 User Manual 1176.8674.02 ─ 07
See also "Converting Shaping Functions and Understanding the Displayed Values"
on page 152.
● About the Linear Functions ................................................................................... 149
● About the Detroughing Function ........................................................................... 149
● About the Polynomial Function ............................................................................. 150
● About the Shaping Table .......................................................................................151
● Shaping Function in Raw Data Format ................................................................. 152
● Converting Shaping Functions and Understanding the Displayed Values ............152
About the Linear Functions
The linear shaping can be used for less demanding applications, simple analysis, and
the first interactions by designing the optimum envelope shape. Because the shaping
gain of the linear function is 0 dB, in "Envelope Voltage Adaptation > Manual" mode
this function is suitable for determining the "Pre-/Post-Gain" values (see
Example "Cal-
culating the current V
CC
in "Manual" mode" on page 156).
Provided are two linear functions, where each of them depends on the "Envelope Volt-
age Adaptation" mode:
●
Linear (Voltage)
–
f(x) = x in "Auto Normalized/Manual"
– f(x) = b*x + V
cc,min
in "Auto Power"
●
Linear (Power)
–
f(x) = x
2
in "Auto Normalized/Manual"
–
f(x) = b*x
2
+ V
cc,min
in "Auto Power"
Where:
●
the variable x depends on the "Envelope Voltage Adaptation" mode, see Table 7-6 .
●
The constant b is calculated as:
b = (V
cc,max
- V
cc,min
)/(V
in,max
- V
in,min
)
See also "Converting Shaping Functions and Understanding the Displayed Values"
on page 152.
About the Detroughing Function
Detroughing functions are well-defined mathematical functions that prevent that the
supply voltage V
cc
drops down to zero or falls under specified limits. That is, they pre-
vent that the signal is clipped.
Provided are the following functions:
●
f(x) = x + d*e
-x/d
●
f(x) = 1 - (1 - d)*cos(x*pi/2)
●
f(x) = d + (1 - d)*x
a
Where:
●
x is a variable, that depends on the "Envelope Voltage Adaptation" mode, see
Table 7-6
●
a is the Exponent (a)
Generation of Envelope Tracking Signals