TDA5235
Functional Description
input data
telegram
signal power
better FAR
performance
SDTHR level area
better
MER/BER
performance
high SDTHR level
low SDTHR level
Figure 16
Signal Detector Threshold Level
Quick Procedure to Determine Signal and Noise Detector Thresholds
Preparation
A setup is required with original RF hardware as in the final application. The values of
SPWR and NPWR can be read via the final application.
A complete configuration file using right modulation, data rate and Run Mode Slave,
must be prepared and downloaded to the TDA5235.
Signal Detector Threshold for ASK
Take 500 readings of SPWR (50 are also possible, but this leads to less accurate results)
with no RF input signal applied (=noise only). Calculate average and Standard Deviation.
Signal Detector Threshold is average plus 2 times the Standard Deviation. To load the
x_SIGDET0/1 register the calculated value must be rounded and converted to
hexadecimals. For a final application, the Signal Detector Threshold should be varied to
optimize the false alarm rate and the sensitivity.
Signal and Noise Detector Thresholds for FSK
Signal Detector Threshold
Do 500 (50) readings of SPWR with no RF input signal applied (=noise only). Calculate
average and Standard Deviation. Signal Detector Threshold is average plus 2 times the
Standard Deviation. Of course this value has to be rounded and converted to
Data Sheet
40
V1.0, 2010-02-19
INFINEON [ Infineon ]
