RF69 datasheet(30/81 Pages) ETC2

30 / 81 page

RF69

Page 30

Tel: +86-755-82973805 Fax: +86-755-82973550 E-mail: sales@hoperf.com http://www.hoperf.com

3.4.12.1. 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.

Note that the noise floor of the receiver at the demodulator input depends on:

 The noise figure of the receiver.

 The gain of the receive chain from antenna to base band.

 The matching - including SAW filter if any.

 The bandwidth of the channel filters.

It is therefore important to note that the setting of OokFixedThresh will be application dependant. The following procedure

is recommended to optimize OokFixedThresh.

Set RF69 in OOK Rx mode Adjust

Bit Rate, Channel filter BW Default

OokFixedThresh setting

No input signal

Continuous Mode

Monitor DIO2/DATA pin

Increment

OokFixedThresh

Glitch activity

on DATA ?

Optimization complete

Figure 12. Floor Threshold Optimization

The new floor threshold value found during this test should be used for OOK reception with those receiver settings.

3.4.12.2. Optimizing OOK Demodulator for Fast Fading Signals

A sudden drop in signal strength can cause the bit error rate to increase. For applications where the expected signal drop

can be estimated, the following OOK demodulator parameters OokPeakThreshStep and OokPeakThreshDec can be

optimized as described below for a given number of threshold decrements per bit. Refer to RegOokPeak to access those

settings.

3.4.12.3. Alternative OOK Demodulator Threshold Modes

In addition to the Peak OOK threshold mode, the user can alternatively select two other types of threshold detectors:

 Fixed Threshold: The value is selected through OokFixedThresh

 Average Threshold: Data supplied by the RSSI block is averaged, and this operation mode should only be used

with DC-free encoded data.

RF69 Datasheet(PDF) 30 Page - List of Unclassifed Manufacturers