CC112X/CC1175
SWRU295C
Page 41 of 108
6
Transmit Configuration
6.1
PA Output Power Programming
PA power ramping is used to improve spectral efficiency of the system by reducing the out of band
signal energy created by abrupt changes in the output power. PA output power ramping is used when
starting/ending a transmission and this feature is always enabled. The power ramping is very flexible
and can be controlled by a configurable, piecewise linear function.
The RF output power level from the device is programmed with the
register field. The power level resolution is 0.5 dB.
18
2
1
_
_
Power
Output
RAMP
POWER
PA
Equation 18: Output Power
12
Where 3 ≤
≤ 64
The shaped power ramping is controlled by the
register. The shaped power ramp up curve
passes through two intermediate power levels from off-state to programmed output power level
.
The intermediate power levels and total ramp time can be
configured. For the shaped ramp up the output power level is split into 16 sections (see
where 1 equals the output power level). The two intermediate power levels are defined using these
16 sections. The first intermediate power level can be programmed within the power level range 0 -
7/16 through
. The second intermediate power level can be programmed within
power range of 0.5 - 15/16 through
. In Figure 15,
FIRST_IPL = 011b
and
SECOND_IPL = 110b
.
●
●
●
●
●
0
8/16
1
●
●
0
1/3
2/3
1
Configurable ramping levels
Configurable: 3/8, 3/2, 3, 6 Ts
Figure 15: PA Power Ramping Control (configurable in the grey area)
The PA ramp up time (and ramp down time) is
3
/
8
,
3
/
2
, 3, or 6 symbols and is configured through
6.2
OOK/ASK Bit Shaping
When using OOK/ASK bit shaping is implemented and the the OOK/ASK shape length is
1
/
32
,
1
/
16
,
1
/
8
,
or
1
/
4
symbols (configured through
).
12
This equation is an approximation. SmartRF Studio provides recommended values for different
output powers based on characterization.