TDA5225 Datasheet, PDF (38/176 Pages) Infineon Technologies AG – Enhanced Sensitivity Multi-Channel Quad-Configuration Receiver

TDA5225
Functional Description
wanted signal
interferer
wanted signal
Figure 17
noise floor
RSSI Blocking Thresholds
x_WURSSIBHy
x_WURSSIBLy
x_WURSSITHy
Threshold evaluation procedure
A statistical noise floor evaluation using read register RSSIPMF (RMS operation) leads
to the threshold x_WURSSITHy. The interferer thresholds x_WURSSIBLy and
x_WURSSIBHy are disabled when they are set to their default values.
For evaluation of the interferer thresholds, either use register RSSIPMF for RMS
operation or during SPM and WU (Wake-Up) on RSSI use register RSSIPWU to
statistically evaluate the interferer band. Finally the thresholds x_WURSSIBLy and
x_WURSSIBHy can be set. Further details can be seen in Figure 10, Chapter 2.4.7
RSSI Peak Detector and Chapter 2.6.2.2 Constant On-Off Time (COO).
NOTE: If e.g. an interferer ends/starts too close after/to the beginning/end of the
observation time, then a decision level error can arise. This is due to the filter dynamics
(settling time). Further, for interferer thresholds evaluation in SPM this changes interferer
statistics. Several interferer measurements are recommended to suppress this, what
makes sense anyway for a better distribution.
Data Sheet
38
V1.0, 2010-02-19