TDA5230 Datasheet, PDF (85/186 Pages) Infineon Technologies AG – Universal Low Power ASK/FSK Single Conversion Multi-Channel Image-Reject Receiver

TDA523x
Functional Description
The next diagram shows the system characteristics to consider in choosing the best
Signal Detector level. On the one hand, achieving good FAR (False Alarm Rate)
performance that a higher threshold level must be set, but the MER/BER (Message Error
Rate/Bit Error Rate) performance (high SIGDET level signal) will decrease. On the other
hand, the MER/BER performance can be increased by setting smaller threshold levels
but then the FAR performance (low SIGDET level signal) will worsen.
input data
signal power
better FAR
performance
SDTHR level area
high SDTHR level
telegram
optional bridged by
the sigdet counter
better MER
performance
low SDTHR level
Figure 42 Signal Detection Threshold Level
Quick Procedure to Determine Signal and Noise Detector Thresholds:
Preparation
A set up is required with original RF hardware as in the final application. The values of
ASKNP and FSKNP can be read via the final application or using the TDA523x Explorer.
A complete configuration file using right modulation, data rate and Run Mode Slave,
must be prepared using the IAF TDA523x Configuration Tool and downloaded to the
TDA523x.
Signal Detector Threshold for ASK
Take 500 readings of ASKNP (50 are also possible, but this leads to less accurate
results) with no RF input signal applied (=noise only). Calculate average and Standard
Deviation (automatically done by TDA523x Explorer). Signal Detector Threshold is
average plus 2 times the standard deviation. To load the SIGDET 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
Data Sheet
81
Version 4.0, 2007-06-01