RFM22B-868-D QUASAR, RFM22B-868-D Datasheet - Page 28

• Manufacturer Part Number: RFM22B-868-D
• Description: MODULE, TRANSCEIVER, 20DB, 868MHZ
• Manufacturer: QUASAR

Specifications of RFM22B-868-D

• Modulation Type: FSK, GFSK, OOK
• Data Rate Max: 256Kbps
• Sensitivity: -121dBm
• Supply Voltage Range: 1.8V To 3.6V
• Supply Current: 85mA
• Interface Type: SPI
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

R F M 2 2 B / 2 3 B
4. Modulation Options
4.1. Modulation Type
The
(GFSK), Frequency Shift Keying (FSK), and On-Off Keying (OOK). GFSK is the recommended modulation type
as it provides the best performance and cleanest modulation spectrum. Figure 12 demonstrates the difference
between FSK and GFSK for a Data Rate of 64 kbps. The time domain plots demonstrate the effects of the Gaussian
filtering. The frequency domain plots demonstrate the spectral benefit of GFSK over FSK. The type of
modulation is selected with the modtyp[1:0] bits in "Register 71h. Modulation Mode Control 2". Note that it is also
possible to obtain an unmodulated carrier signal by setting modtyp[1:0] = 00.
28
RFM22B/23B supports
Tel: [phone]
TX Modulation Time Domain Waveforms -- FSK vs. GFSK
-0.5
-1.0
-1.5
-0.5
-1.0
1.5
1.0
0.5
0.0
1.0
0.5
0.0
0
50
100
modtyp[1:0]
150
00
01
10
11
350
200
Fax: [phone]
three
400
Figure 12. FSK vs GFSK Spectrums
GFSK (enable TX Data CLK when direct mode is used)
250
450
different
time, usec
300
500
modulation options:
Unmodulated Carrier
Modulation Source
E-mail: [e-mail]
-100
-100
TX Modulation Spectrum -- FSK vs GFSK (Continuous PRBS)
-20
-40
-60
-80
-20
-40
-60
-80
-250
OOK
FSK
DataRate
-200
64000.0
-150
Gaussian
TxDev
-100
32000.0
150
-50
Frequency
BT_Filter
200
freq, KHz
0.5
0 50
ModIndex
Shift
100
1.0
Keying
250