PR
EL
IMI
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SW71122
MLX71122 RF Receiver
Programming Software Manual
39011 71122 01
Page 13 of 21
SW71122-Manual
Rev. 004
Aug/11
5.2 Gain Control – Tab
The
Gain Control
tab is split up into an upper part defining the static gain of different receiver blocks and a
lower part for controlling the
Automatic Gain Control
(AGC).
The frame
Receiver Gain Settings
contains the following controls:
5.2.1
LNA
Four different LNA gain settings are possible. Since the absolute gain depends on the input matching of the
LNA and on the quality factor of the tank circuit, only settings relative to the default gain are selectable. The
gain is controlled by the core current of the LNA.
Possible selections are: Default -20dB, Default -6dB, Default -2dB, Default
5.2.2
IF Filter
The Intermediate Frequency Filter (IFF) has four gain settings: -14dB, -6dB, 0dB (default), +6dB.
These are absolute voltage gains from the filter input to the input of the Intermediate Frequency Amplifier
(IFA). Default gain is +6dB. If MFO is set to IF-out, 14dB have to be added for the gain from the filter input to
the unloaded MFO-pin and -9dB have to be added for the gain from the filter input to the MFO-pin with 50
Ω
load. The output resistance of the MFO-buffer is about 610
Ω
.
5.2.3
1
st
Mixer Gain
These radio buttons set the MIX1GAIN bit. It specifies the gain of the 1
st
mixer.
Possible selections are: 0dB, +14dB (default)
