CC2400_08 Datasheet, PDF (43/84 Pages) Texas Instruments – 2.4 GHz Low-Power RF Transceiver

CC2400
100
80
60
40
20
0
-500 -450 -400 -350 -300 -250 -200 -150 -100 -50 0 50 100 150 200 250 300 350 400 450 500 550
-20
-40
-60
-80
-100
Frequency offset [kHz]
Figure 21. AFC value vs. frequency offset
AFC with settle = 8
AFC with settle = 4
AFC with settle = 2
AFC with settle = 1
33 Linear IF and AGC Settings
CC2400 is based on a linear IF chain
where the signal amplification is done in
an analog VGA (variable gain amplifier).
The gain of the VGA is controlled by the
digital part of the IF-chain after the ADC
(Analog Digital Converter).
The AGC (Automatic Gain Control) loop
ensures that the ADC operates inside its
dynamic range by using an analog/digital
feedback loop.
The AGC characteristics are set through
the AGCCTRL, AGCTST0, AGCTST1 and
AGCTST2 registers.
Note that the RSSI function does not take
AGC settings into consideration if the AGC
settings are overridden.
SWRS042A
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