Data Sheet

Page 42
RFM95/96/97/98
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WIRELESS & SENSING PRELIMINARY DATASHEET
Table 64 Bit Rate Examples
Type
BitRate
(15:8)
BitRate
(7:0)
(G)FSK
(G)MSK
OOK
Actual BR
(b/s)
Classical modem baud rates
(multiples of 1.2 kbps)
0x68
0x2B
1.2 kbps
1.2 kbps
1200.015
0x34
0x15
2.4 kbps
2.4 kbps
2400.060
0x1A
0x0B
4.8 kbps
4.8 kbps
4799.760
0x0D
0x05
9.6 kbps
9.6 kbps
9600.960
0x06
0x83
19.2 kbps
19.2 kbps
19196.16
0x03
0x41
38.4 kbps
38415.36
0x01
0xA1
76.8 kbps
76738.60
0x00
0xD0
153.6 kbps
153846.1
Classical modem baud rates
(multiples of 0.9 kbps)
0x02
0x2C
57.6 kbps
57553.95
0x01
0x16
115.2 kbps
115107.9
Round bit rates
(multiples of 12.5, 25 and
50 kbps)
0x0A
0x00
12.5 kbps
12.5 kbps
12500.00
0x05
0x00
25 kbps
25 kbps
25000.00
0x80
0x00
50 kbps
50000.00
0x01
0x40
100 kbps
100000.0
0x00
0xD5
150 kbps
150234.7
0x00
0xA0
200 kbps
200000.0
0x00
0x80
250 kbps
250000.0
0x00
0x6B
300 kbps
299065.4
Watch Xtal frequency
0x03
0xD1
32.768 kbps
32.768 kbps
32753.32
4.2.2. FSK/OOK Transmission
4.2.2.1. FSK Modulation
FSK modulation is performed inside the PLL bandwidth, by changing the fractional divider ratio in the feedback loop of the
PLL. The high resolution of the sigma-delta modulator, allows for very narrow frequency deviation. The frequency deviation
F
DEV
is given by:
F
DEV
= F
STEP
× Fdev (13,0)
To ensure correct modulation, the following limit applies:
F
DE V
+
-----
R
--
≤ (250 )kHz
2