RFM92 Datasheet, PDF (47/126 Pages) List of Unclassifed Manufacturers – Low Power Long Range Transceiver Module

RFM92W/93W V3.0
Alternative OOK Demodulator Threshold Modes
In addition to the Peak OOK threshold mode, the user can alternatively select two other types of threshold detectors:
Š Fixed Threshold: The value is selected through OokFixedThresh
Š Average Threshold: Data supplied by the RSSI block is averaged (this operation mode should only be used with DC-
free encoded data).
4.2.3.3. Bit Synchronizer
The bit synchronizer provides a clean and synchronized digital output based upon timing recovery information gleaned
from the received data edge transitions. Its output is made available on pin DIO1/DCLK in Continuous mode and can be
disabled through register settings. However, for optimum receiver performance, especially in Continuous receive mode, its
use is strongly advised.
The Bit Synchronizer is automatically activated in Packet mode. Its bit rate is controlled by BitRateMsb and BitRateLsb in
RegBitrate.
Raw demodulator
output
(FSK or OOK)
BitSync Output To
pin DATA and
DCLK in continuous
mode
DATA
DCLK
Figure 16. Bit Synchronizer Description
To ensure correct operation of the Bit Synchronizer the following conditions have to be satisfied:
Š A preamble (0x55 or 0xAA) of at least 12 bits is required for synchronization, the longer the synchronization phase is the
better the ensuing packet detection rate will be.
Š The subsequent payload bit stream must have at least one edge transition (either rising or falling) every 16 bits during
data transmission.
Š The absolute error between transmitted and received bit rate must not exceed 6.5%.
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