Data Sheet

Page 42
RFM95/96/97/98(W)
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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)
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
Classical modem baud rates
(multiples of 1.2 kbps)
0x00 0xD0 153.6 kbps 153846.1
0x02 0x2C 57.6 kbps 57553.95
Classical modem baud rates
(multiples of 0.9 kbps)
0x01 0x16 115.2 kbps 115107.9
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
Round bit rates
(multiples of 12.5, 25 and
50 kbps)
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