tda5225 Infineon Technologies Corporation, tda5225 Datasheet - Page 36

• Manufacturer Part Number: tda5225
• Description: Enhanced Sensitivity Multi-channel Quad-conf Igurat Ion Receiver With Digital Slicer
• Manufacturer: Infineon Technologies Corporation

Notes:
1. The upper RF input level must stay well below the saturation level of the receiver (see
Chapter 2.4.6.4 Digital Automatic Gain Control Unit
2. The lower RF input level must stay well above the noise level of the receiver
3. If IF Attenuation is trimmed, this has to be done before trimming of RSSI
4. If RSSI needs to be trimmed in a higher input power range the AGCGAIN must be set
accordingly
2.4.8
Figure 15
The digital baseband receiver comprises a matched data filter and a data slicer. The
received data signal is accessible via one of the port pins.
2.4.8.1
The data filter is a matched filter (MF). The frequency response of a matched filter has
ideally the same shape as the power spectral density (PSD) of the originally transmitted
signal, therefore the signal-to-noise ratio (SNR) at the output of the matched filter
becomes maximum. The input sampling rate of the baseband receiver has to be
Data Sheet
Digital Baseband (DBB) Receiver
Demodulator
Data Filter
From ASK/
Functional Block Diagram Digital Baseband Receiver
FSK
samples
per chip
8 to 16
(Sliced RAW Data for
external processing )
RAW Data Slicer
Matched Filter
for external
processing
adjust_length
Invert
DATA
Data
36
DINVEXT
for external processing )
(Matched Filtered Data
fs
DATA_MATCHFIL
(AGC))
fractional SRC
out
/ fs
Invert
SIGN
MUX
Data
in
= 0.5 … 1.0
Functional Description
bypass
SRC
V1.0, 2010-02-19
TDA5225