MLX71122_16 Datasheet, PDF (32/59 Pages) Melexis Microelectronic Systems – 300 to 930MHz FSK/FM/ASK Receiver

MLX71122
300 to 930MHz FSK/FM/ASK Receiver
Datasheet
3.3.7. Automatic Gain Control (AGC)
The Automatic Gain Control (AGC) can be activated in SPI mode with AGCEN (see 4.1.4). By default, it is
turned off. It uses the RSSIH and RSSIL signals of the IF amplifier to determine whether the gain has to be
increased or decreased. The gain will be decreased beginning with the gain of the last stage. The gain
increase works vice versa. The AGC circuit controls the gain of the LNA, and of mixer 1 and mixer 2. To
avoid rapid gain switching, caused by short signal strength fluctuations or during ASK reception, the gain
control operates with a time delay that can be programmed via AGCDEL (see 4.1.4). The time delay also
depends on the PFD frequency of the IF filter auto-tuning circuit. There is no delay by default. AGCMODE
(see 4.1.5), a second setting, determines whether the delay is applied for gain increase and decrease or
only for gain increase. By default, a delay for increase and decrease is used.
REVISION 014 – AUGUST, 2016
390 10 71122 01
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