Blocker detection based automatic gain control

Abstract

Modular gain control based on blocker signal detection is disclosed herein. In a multi-stage gain control scheme for a receiver, the input stage gain or the pre-mixing stage gain can be controlled for effective blocker rejection based on detecting a blocker signal at a mixer, and the output stage gain or the post-mixing stage gain can be controlled to restore and maintain an appropriate output level after pre-mixing gain reduction performed for blocker rejection. Accordingly, the RF communication systems herein can include multiple loops for providing AGC. In particular, an RF communication system can include a main loop and a blocker loop used to override the main loop when the blocker signal is detected. In certain configurations, the blocker loop reduces the gain of an RF VGA, while the main loop will increase the gain of an IF VGA to restore the output power.

Description

technical field

[0001] Embodiments of the present invention relate to electronic systems, and more particularly to automatic gain control for radio frequency communication systems. Background technique

[0002] Automatic gain control (AGC) can be used in a variety of applications, including radio frequency (RF) communication systems. AGC can be implemented using a variable gain amplifier (VGA) in a loop, such as a feedback or feedforward AGC loop.

[0003] For example, an RF communication system may include a feedback AGC loop that adjusts the VGA control voltage with reference to a reference voltage. The presence of blocking or cutoff frequency signals near the receiver of an RF communication system can affect gain and signal-to-noise ratio (SNR). Achieving proper blocking inhibition of this blocking signal is challenging. Contents of the invention

[0004] The methods and apparatus of the described technology each have several aspects, no single one of which is solely...

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