tda5235 Infineon Technologies Corporation, tda5235 Datasheet - Page 37

• Manufacturer Part Number: tda5235
• Description: Enhanced Sensitivity Double-configuration Receiver With Digital Baseband Processing
• Manufacturer: Infineon Technologies Corporation

Recommended Digital Trimming Procedure
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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
Data Sheet
Download configuration file (Run Mode Slave; RSSISLOPE, RSSIOFFS set to
default, i.e. RSSISLOPE=1, RSSIOFFS=0)
Turn off AGC (AGCSTART=0) and set gain to AGCGAIN=0
Apply P
Read RSSIRX eleven times (minimum 10 ms in-between readings), use average of
last ten readings (always), store as RSSIM1
Apply P
Read RSSIRX eleven times (minimum 10 ms in-between readings), use average of
last ten readings (always), store as RSSIM2
Calculate measured RSSI slope SLOPEM=(RSSIM2-RSSIM1)/(P
Adjust
RSSISLOPE=SLOPER/SLOPEM
Adjust
RSSIOFFS=(RSSIR2-RSSIM2)+(SLOPEM-SLOPER)*P
The new values for RSSISLOPE and RSSIOFFS have to be added to the
configuration!
IN1
IN2
RSSIOFFS
RSSISLOPE
= -85 dBm RF input signal
= -65 dBm RF input signal
for
for
required
required
37
value
RSSI
RSSIR2
slope
(AGC))
IN2
SLOPER
Functional Description
at
P
IN2
IN2
-P
V1.0, 2010-02-19
IN1
as
as
)
TDA5235
follows:
follows: