CC2400 Chipcon AS, CC2400 Datasheet - Page 37

• Manufacturer Part Number: CC2400
• Description: 2.4 GHz RF Transceiver
• Manufacturer: Chipcon AS

FSK Modulation Formats
The data modulator can modulate 2FSK,
(which is two level FSK), or GFSK, which
is a Gaussian filtered FSK with BT=0.5 at
1 Mbps (for lower data rates BT will be
higher).
The purpose of the GFSK is to make a
more bandwidth efficient system. The
modulation and the Gaussian filtering are
Built-in Test Pattern Generator
The
generator that can generate a PN9
pseudo
MDMTST0.TX_PRNG bit enables the PN9
generator.
The PN9 pseudo random sequence is
defined by the polynomial x
Receiver Channel Bandwidth
In order to meet different channel width
and channel spacing requirements, the
receiver’s digital channel filter bandwidth
is programmable. It can be programmed
from 125 to 1000 kHz.
The GRDEC.CHANNEL_DEC[1:0] register
bits control the bandwidth.
The
selectable channel bandwidths.
Chipcon AS
Channel filter
bandwidth
CC2400
[kHz]
1000
500
250
125
table
random
SmartRF
has a built-in test pattern
below
GRDEC.CHANNEL_DEC[1:0]
®
CC2400 PRELIMINARY Datasheet (rev. 1.1), 2003-10-02
sequence.
summarizes
[binary]
9
00
01
10
11
+ x
5
+ 1.
The
the
SmartRF
done
GRMDM.TX_GAUSSIAN_FILTER
enables the GFSK.
However, if GFSK modulation is used
together with a data rate of 1 Mbps, it is
recommended to use a preamble length of
32 bytes as otherwise packet error
performance can be affected.
The PN9 generator can be used for
transmission
measuring
occupied bandwidth.
There is a tradeoff between selectivity and
accepted
applications where larger frequency drift is
expected (depends on the accuracy of the
crystal), the filter bandwidth should be
increased, at the expense of reduced
adjacent channel rejection (ACR).
It is strongly recommended to use one of
the
datarates and channel bandwidths as
described in the section “Data Rate
Programming” on page 38.
three
internally
frequency
modulation
settings
of
®
‘real-life’
in
CC2400
the
for
tolerance.
bandwidth
data
chip.
over-the-air
Page 37 of 73
when
The
bit
or
In