RF65 Datasheet, PDF (24/72 Pages) List of Unclassifed Manufacturers – Low Power Integrated UHF Receiver With -120dBm High Sensitivity

ADVANCED COMMUNICATIONS & SENSING
RF65
DATASHEET
3.4.13. 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 8:
RSSI
[dBm]
„‟Peak -6dB‟‟ Threshold
„‟Floor‟‟ threshold defined by
OokFixedThresh
Noise floor of
receiver
Zoom
Decay in dB as defined in
OokPeakThreshStep
Fixed 6dB difference
Time
Period as defined in
OokPeakThreshDec
Figure 8. OOK Peak Demodulator Description
In peak threshold mode the comparison threshold level is the peak value of the RSSI, reduced by 6dB. In the absence of
an input signal, or during the reception of a logical "0", the acquired peak value is decremented by one
OokPeakThreshStep every OokPeakThreshDec period.
When the RSSI output is null for a long time (for instance after a long string of "0" received, or if no transmitter is present),
the peak threshold level will continue falling until it reaches the "Floor Threshold", programmed in OokFixedThresh.
The default settings of the OOK demodulator lead to the performance stated in the electrical specification. However, in
applications in which sudden signal drops are awaited during a reception, the three parameters should be optimized
accordingly.
3.4.13.1. Optimizing the Floor Threshold
OokFixedThresh determines the sensitivity of the OOK receiver, as it sets the comparison threshold for weak input signals
(i.e. those close to the noise floor). Significant sensitivity improvements can be generated if configured correctly.
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