TDA5240 Datasheet, PDF (52/284 Pages) Infineon Technologies AG – Enhanced Sensitivity Multi-Channel Quad-Configuration Receiver

TDA5240
Functional Description
x_WURSSIBHy, where y represents the actual RF channel. These two thresholds can
be evaluated during normal operation of the application to handle the actual interferer
environment.
The blocking window can be disabled by setting x_WURSSIBHy to the minimum value
and x_WURSSIBLy to the maximum value.
wanted signal
interferer
wanted signal
Figure 24
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.
Wake-Up on RSSI can also be applied as additional criterion when already using a
Wake-Up on Data criterion in Constant On-Off (COO) Mode.
Further details can be seen in Figure 10, Chapter 2.4.7 RSSI Peak Detector,
Chapter 2.6.2.2 Constant On-Off Time (COO) and Chapter 2.6.2.3 Fast Fall Back to
SLEEP (FFB).
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
52
V4.0, 2010-02-19