SX1231 SEMTECH [Semtech Corporation], SX1231 Datasheet - Page 27

• Manufacturer Part Number: SX1231
• Description: Low Power Integrated UHF Transceiver
• Manufacturer: SEMTECH [Semtech Corporation]

3.5.10. FSK Demodulator
The FSK demodulator of the SX1231 is designed to demodulate FSK, GFSK, MSK and GMSK modulated signals. It is
most efficient when the modulation index of the signal is greater than 0.5 and below 10:
The output of the FSK demodulator can be fed to the Bit Synchronizer (described in section 3.5.12), to provide the
companion processor with a synchronous data stream in Continuous mode.
3.5.11. OOK Demodulator
The OOK demodulator performs a comparison of the RSSI output and a threshold value. Three different threshold modes
are available, configured through bits OokThreshType in RegOokPeak.
The recommended mode of operation is the "Peak" threshold mode, illustrated in Figure 9:
Rev 2 - Nov 2009
ADVANCED COMMUNICATIONS & SENSING
RSSI
[dBm]
Figure 9. OOK Peak Demodulator Description
Zoom
Zoom
Magnitude
Figure 8. Cordic Extraction
Real-time
OokPeakThreshDec
Decay in dB as defined in
Period as defined in
OokPeakThreshStep
0.5 β
≤
=
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2 F
----------------------
×
Q(t)
BR
DEV
Real-time Phase
≤
10
I(t)
Fixed 6dB difference
‘’Peak -6dB’’ Threshold
‘’Floor’’ threshold defined by
OokFixedThresh
Noise floor of
receiver
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