Texas Instruments CC1101 - Page 79

CC1101
SWRS061H Page 79 of 98
0x15: DEVIATN – Modem Deviation Setting
Bit
Field Name
Reset
R/W
Description
7
R0
Not used.
6:4
DEVIATION_E[2:0]
4 (100)
R/W
Deviation exponent.
3
R0
Not used.
2:0
DEVIATION_M[2:0]
7 (111)
R/W
TX
2-FSK/
GFSK/
4-FSK
Specifies the nominal frequency deviation from the carrier for a
„0‟ (-DEVIATN) and „1‟ (+DEVIATN) in a mantissa-exponent
format, interpreted as a 4-bit value with MSB implicit 1. The
resulting frequency deviation is given by:
EDEVIATION
xosc
dev
MDEVIATION
f
f
_
17
2)_8(
2

The default values give ±47.607 kHz deviation assuming 26.0
MHz crystal frequency.
MSK
Specifies the fraction of symbol period (1/8-8/8) during which a
phase change occurs („0‟: +90deg, „1‟:-90deg). Refer to the
SmartRF Studio software [5] for correct DEVIATN setting when
using MSK.
ASK/OOK
This setting has no effect.
RX
2-FSK/
GFSK/
4-FSK
Specifies the expected frequency deviation of incoming signal,
must be approximately right for demodulation to be performed
reliably and robustly.
MSK/
ASK/OOK
This setting has no effect.