SX1276 View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SX1276' PDF : 132 Pages View PDF
SX1276/77/78/79
WIRELESS, SENSING & TIMING
DATASHEET
5.5.6. Channel Filter
The role of the channel filter is to reject noise and interference outside of the wanted channel. The SX1276/77/78/79
channel filtering is implemented with a 16-tap finite impulse response (FIR) filter. Rejection of the filter is high enough that
the filter stop-band performance is not the dominant influence on adjacent channel rejection performance. This is instead
limited by the SX1276/77/78/79 local oscillator phase noise.
Note To respect sampling criterion in the decimation chain of the receiver, the communication bit rate cannot be set at a
higher than twice the single side receiver bandwidth (BitRate < 2 x RxBw)
The single-side channel filter bandwidth RxBw is controlled by the parameters RxBwMant and RxBwExp in RegRxBw:
RxBw = R-----x---B----w----M-----a---F-n---Xt---×-O----2S---R-C--x---B---w----E---x--p----+----2
The following channel filter bandwidths are hence accessible in the case of a 32 MHz reference oscillator:
Table 40 Available RxBw Settings
RxBwMant RxBwExp
(binary/value) (decimal)
10b / 24
7
01b / 20
7
00b / 16
7
10b / 24
6
01b / 20
6
00b / 16
6
10b / 24
5
01b / 20
5
00b / 16
5
10b / 24
4
01b / 20
4
00b / 16
4
10b / 24
3
01b / 20
3
00b / 16
3
10b / 24
2
01b / 20
2
00b / 16
2
10b / 24
1
01b / 20
1
00b / 16
1
Other settings
RxBw (kHz)
FSK/OOK
2.6
3.1
3.9
5.2
6.3
7.8
10.4
12.5
15.6
20.8
25.0
31.3
41.7
50.0
62.5
83.3
100.0
125.0
166.7
200.0
250.0
reserved
Rev. 4 - March 2015
©2015 Semtech Corporation
Page 88
www.semtech.com
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