CC1101
SWRS061H Page 65 of 98
time is reduced from 712/724 µs to 145/157 µs
(26 MHz crystal and TEST0 = 0x09/0B, see
Table 35). The blanking interval between each
frequency hop is then 220/232 µs.
There is a trade off between blanking time and
memory space needed for storing calibration
data in non-volatile memory. Solution 2) above
gives the shortest blanking interval, but
requires more memory space to store
calibration values. This solution also requires
that the supply voltage and temperature do not
vary much in order to have a robust solution.
Solution 3) gives 567 µs smaller blanking
interval than solution 1).
The recommended settings for
TEST0.VCO_SEL_CAL_EN change with
frequency. This means that one should always
use SmartRF Studio [5] to get the correct
settings for a specific frequency before doing a
calibration, regardless of which calibration
method is being used.
28.3 Wideband Modulation when not Using Spread Spectrum
Digital modulation systems under FCC Section
15.247 include 2-FSK, GFSK, and 4-FSK
modulation. A maximum peak output power of
1 W (+30 dBm) is allowed if the 6 dB
bandwidth of the modulated signal exceeds
500 kHz. In addition, the peak power spectral
density conducted to the antenna shall not be
greater than +8 dBm in any 3 kHz band.
Operating at high data rates and frequency
separation, the
CC1101
is suited for systems
targeting compliance with digital modulation
system as defined by FCC Section 15.247. An
external power amplifier such as
CC1190
[21] is
needed to increase the output above +11
dBm. Please refer to DN006 [11] for further
details concerning wideband modulation using
CC1101
and DN036 for wideband modulation at
600 kbps data rate, +19 dBm output power
when using
CC1101
+
CC1101
[25].
28.4 Wireless MBUS
The wireless MBUS standard is a
communication standard for meters and
wireless readout of meters, and specifies the
physical and the data link layer. Power
consumption is a critical parameter for the
meter side, since the communication link shall
be operative for the full lifetime of the meter,
without changing the battery.
CC1101
combined
with
MSP430
is an excellent choice for the
Wireless MBUS standard,
CC1101
is a truly low
cost, low power and flexible transceiver, and
MSP430
a high performance and low power
MCU. For more informati on regarding using
CC1101
for Wireless MBUS applications, see
AN067 [14].
Since the Wireless MBUS standard operates
in the 868-870 ISM band, the radio
requirements must also comply with the ETSI
EN 300 220 and CEPT/ERC/REC 70-03 E
standards.
28.5 Data Burst Transmissions
The high maximum data rate of
CC1101
opens
up for burst transmissions. A low average data
rate link (e.g. 10 kBaud) can be realized by
using a higher over-the-air data rate. Buffering
the data and transmitting in bursts at high data
rate (e.g. 500 kBaud) will reduce the time in
active mode, and hence also reduce the
average current consumption significantly.
Reducing the time in active mode will reduce
the likelihood of collisions with other systems
in the same frequency range.
28.6 Continuous Transmissions
In data streaming applications, the
CC1101
opens up for continuous transmissions at 500
kBaud effective data rate. As the modulation is
done with a closed loop PLL, there is no
limitation in the length of a transmission (open
loop modulation used in some transceivers
Note: The content in the TEST0 register is
not retained in SLEEP state, thus it is
necessary to re-write this register when
returning from the SLEEP state.
Note: The sensitivity and thus transmission
range is reduced for high data rate bursts
compared to lower data rates.
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