RF Receiver Filter Control for Blocker Signal Clipping
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Solution Overview
Problem
Receiver circuits face difficulties in accurately receiving signal information due to high power signals near the signal frequency, leading to signal clipping and range limit exceedance in components like low-pass filters, variable gain amplifiers, and analog-to-digital converters.
Innovation Solution
A receiver circuit design that includes a controller to detect clipping and generate control signals for low-pass filters, variable gain amplifiers, and analog-to-digital converters to attenuate the baseband signal, preventing clipping by adjusting gain or filtering elements such as moving poles in filtering elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high power blocker signals are present near the signal frequency, then the receiver can still attempt to process the signal, but signal clipping occurs and range limits are exceeded in processing components
Solution Approach 1:
The receiver signal path is divided into multiple parallel processing chains: a main signal path and an auxiliary path with adjustable gain. The auxiliary path processes signals with different amplification levels, allowing selective attenuation of blocker signals while preserving weak desired signals. This segmentation enables differential handling of signal components based on their power levels.
Solution Approach 2:
The patent dynamically adjusts the gain parameter of the auxiliary signal path based on detected signal conditions. By changing the amplification parameter in real-time, the system can adapt to varying blocker signal strengths and maintain optimal processing conditions, preventing clipping while ensuring adequate signal levels for accurate reception.
2Reliability
If the receiver processes signals with high power blocker components, then signal information may be lost due to clipping, but adding attenuation mechanisms increases device complexity
Solution Approach 1:
The auxiliary signal path serves multiple functions: it acts as both a signal processing channel and a blocker detection mechanism. The same hardware infrastructure is used for both attenuating strong blocker signals and monitoring signal conditions, reducing the need for separate dedicated components and thereby limiting the increase in device complexity.
Solution Approach 2:
The auxiliary signal path with adjustable gain acts as an intermediary between the raw received signal and the final processed output. This intermediate processing stage allows gradual attenuation of blocker signals before they reach sensitive components, preventing clipping while maintaining a relatively simple overall architecture by using a single mediating path rather than multiple complex filtering stages.
Data Source
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Figure 3
AI summary
A receiver circuit includes an amplifier configured to generate an RF signal based on a received signal, where the RF signal includes an information signal and a blocker signal modulating an RF carrier frequency. The receiver circuit also includes an RF filter connected to the amplifier, where the RF filter is configured to selectively attenuate the blocker signal.