Texas Instruments CC1101 User Manual

CC1101
SWRS061H Page 43 of 98
16.2 Minimum Shift Keying
When using MSK
2
, the complete transmission
(preamble, sync word, and payload) will be
MSK modulated.
Phase shifts are performed with a constant
transition time. The fraction of a symbol period
used to change the phase can be modified
with the DEVIATN.DEVIATION_M setting.
2
Identical to offset QPSK with half-sine
shaping (data coding may differ).
This is equivalent to changing the shaping of
the symbol. The DEVIATN register setting has
no effect in RX when using MSK.
When using MSK, Manchester
encoding/decoding should be disabled by
setting MDMCFG2.MANCHESTER_EN=0.
The MSK modulation format implemented in
CC1101 inverts the sync word and data
compared to e.g. signal generators.
16.3 Amplitude Modulation
CC1101 supports two different forms of
amplitude modulation: On-Off Keying (OOK)
and Amplitude Shift Keying (ASK).
OOK modulation simply turns the PA on or off
to modulate ones and zeros respectively.
The ASK variant supported by the CC1101
allows programming of the modulation depth
(the difference between 1 and 0), and shaping
of the pulse amplitude. Pulse shaping
produces a more bandwidth constrained
output spectrum.
When using OOK/ASK, the AGC settings from
the SmartRF Studio [5] preferred FSK/MSK
settings are not optimum. DN022 [16] give
guidelines on how to find optimum OOK/ASK
settings from the preferred settings in
SmartRF Studio [5]. The DEVIATN register
setting has no effect in either TX or RX when
using OOK/ASK.
17 Received Signal Qualifiers and Link Quality Information
CC1101 has several qualifiers that can be used
to increase the likelihood that a valid sync
word is detected:
 Sync Word Qualifier
 Preamble Quality Threshold
 RSSI
 Carrier Sense
 Clear Channel Assessment
 Link Quality Indicator
17.1 Sync Word Qualifier
If sync word detection in RX is enabled in the
MDMCFG2 register, the CC1101 will not start
filling the RX FIFO and perform the packet
filtering described in Section 15.3 before a
valid sync word has been detected. The sync
word qualifier mode is set by
MDMCFG2.SYNC_MODE and is summarized in
Table 30. Carrier sense in Table 30 is
described in Section 17.4.

Texas Instruments CC1101 Specifications

General

Brand	Texas Instruments
Model	CC1101
Category	Transceiver
Language	English