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CC112X/CC1175
SWRU295C
Page 29 of 108
4.2
Data Rate Programming
The data rate used in transmit and the data rate expected in receive is programmed by the
configuration settings. The data rate, R
DATA
, is given by
Equation 6 and Equation 7 and is in ksps. Note that
is 20 bits wide and consists of the
found in
, and
XOSC
E
DATARATE
DATA
f
M
DATARATE
R
39
_
20
2
2
)
_
2
(
Equation 6: Data Rate (
DEVIATION_E
> 0)
XOSC
DATA
f
M
DATARATE
R
38
2
_
Equation 7: Data Rate (
DEVIATION_E
= 0)
Equation 8 and Equation 9 can be used to find suitable register values for a given data rate.
20
2
log
_
39
2
XOSC
DATA
f
R
E
DATARATE
Equation 8:
DATARATE_E
20
_
39
2
2
2
_
E
DATARATE
XOSC
DATA
f
R
M
DATARATE
Equation 9:
DATARATE_M
If
is rounded to the nearest integer and becomes 2
20
, one should increment
and use
DATARATE_M = 0
instead.
The data rate can be set up to 100 ksps with the minimum step size according to
Error! Reference source not found.
.
Min Data Rate
[ksps]
Typical Data Rate
[ksps]
Max Data Rate
[ksps]
Data Rate Step Size
[ksps]
0
0.04
0.15
0.00014
0.15
0.25
0.3
0.00014
0.61
1.2
1.22
0.0006
1.22
2.4
2.44
0.001
2.44
4.8
4.88
0.002
4.88
9.6
9.76
0.005
19.5
25
39.0
0.018
39.0
50
78.1
0.037
78.1
100
125
0.074
Table 14: Data Rate Step Size
The data rate is programmed as symbol rate meaning that for 4-(G)FSK, DSSS mode, or Manchester
coding, the bit rate and symbol rate is not equal. Table 15 shows the relationship between bit rate and
symbol rate.
Modulation Format
Bit Rate/Symbol Rate Ratio
2-(G)FSK/OOK/ASK
1
Symbol
Bit
R
R
Manchester
Coding
2
1
Symbol
Bit
R
R
4-(G)FSK
2
Symbol
Bit
R
R
DSSS Mode
actor
SpreadingF
R
R
Symbol
Bit
1
Table 15: Bit Rate vs. Symbol Rate