Data Sheet

Page 21
RFM95/96/97/98(W)
Tel: + 86-755-82973805 Fax: [phone] E-mail: [e-mail] http:/ / www.hoperf.com
All major parameters of the RF front end and digital state machine are fully configurable via an SPI interface which gives
access to RFM95/96/97/98(W)’s configuration registers. This includes a mode auto sequencer that oversees the
transition and calibration of the RFM95/96/97/98(W) between intermediate modes of operation in the fastest time possible.
The RFM95/96/97/98(W) are equipped with both standard FSK and long range spread spectrum (LoRa
TM
) modems.
Depending upon the mode selected either conventional OOK or FSK modulation may be employed or the LoRa
TM
spread
spectrum modem.
3.1. LoRa
TM
Modem
The LoRa
TM
modem uses a proprietary spread spectrum modulation technique. This modulation, in contrast to legacy
modulation techniques, permits an increase in link budget and increased immunity to in-band interference. At the same
time the frequency tolerance requirement of the crystal reference oscillator is relaxed - allowing a performance increase
for
a
reduction in system cost. For a fuller description of the design trade-offs and operation of the RFM95/96/97/98(W)
please consult Section 4.1 of the datasheet.
3.2. FSK/OOK Modem
In FSK/OOK mode the RFM95/96/97/98(W) supports standard modulation techniques including OOK, FSK, GFSK, MSK
and GMSK. The RFM95/96/97/98(W) is especially suited to narrow band communication thanks the low-IF architecture
employed and the built-in AFC functionality. For full information on the FSK/OOK modem please consult Section 4.2 of this
document.