CC1110Fx / CC1111Fx
radio will enter RX_OVERFLOW state and the
with RFIF.IRQ_DONE. An SIDLE strobe needs
RFIF.IRQ_RXOVF flag will be set together
to be issued to return to IDLE state.
14.9 Modulation Formats
The MSK modulation format implemented in
CC1110Fx/CC1111Fx inverts the sync word and
data compared to e.g. signal generators.
CC1110Fx/CC1111Fx supports frequency and
phase shift modulation formats. The desired
modulation
format
is
set
in
the
MDMCFG2.MOD_FORMAT register.
14.9.3 Amplitude Modulation
Optionally, the data stream can be Manchester
coded by the modulator and decoded by the
demodulator. This option is enabled by setting
CC1110Fx/CC1111Fx supports two different forms
of amplitude modulation: On-Off Keying (OOK)
and Amplitude Shift Keying (ASK).
MDMCFG2.MANCHESTER_EN=1.
Manchester
encoding is not supported at the same time as
using the FEC/Interleaver option.
OOK modulation simply turns on or off the PA
to modulate 1 and 0 respectively.
The ASK variant supported by the
CC1110Fx/CC1111Fx allows programming of the
modulation depth (the difference between 1
and 0), and shaping of the pulse amplitude.
Pulse shaping will produce a more bandwidth
constrained output spectrum.
14.9.1 Frequency Shift Keying
2-FSK can optionally be shaped by a Gaussian
filter with BT=1, producing a GFSK modulated
signal.
The frequency deviation is programmed with
the DEVIATION_M and DEVIATION_E values
in the DEVIATN register. The value has an
exponent/mantissa form, and the resultant
deviation is given by:
fref
217
fdev
=
⋅(8 + DEVIATION _ M )⋅2DEVIATION _ E
The symbol encoding is shown in Table 67.
Format
Symbol
Coding
2-FSK/GFSK
‘0’
‘1’
– Deviation
+ Deviation
Table 67: Symbol Encoding for 2-FSK/GFSK
Modulation
14.9.2 Minimum Shift Keying
When using MSK19, 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. This is
equivalent to changing the shaping of the
symbol.
19
Identical to offset QPSK with half-sine
shaping (data coding may differ)
SWRS033E
Page 195 of 239
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