LC Notch Filter for RF Receiver Interference Attenuation
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Solution Overview
Problem
Radio frequency receivers face challenges in processing signals with strong interference, which increases the linearity and filtering requirements for downstream processing blocks, particularly in transceivers where transmitter leakage causes interference.
Innovation Solution
Incorporating an LC based notch filter in the radio frequency receiver circuitry to down-convert and filter out interference components, with the notch centered within the interference frequency range, thereby attenuating interference and relaxing the requirements for subsequent processing blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the receiver processes radio frequency signals with strong interference components, then the receiver can maintain basic signal processing capability, but the linearity and filtering requirements of downstream processing blocks increase significantly
Solution Approach 1:
The patent applies preliminary action by inserting an interference filtering stage between the LNA and mixer to remove interference components before down-conversion. This preliminary filtering prevents interference from propagating to downstream blocks, thereby reducing their linearity and filtering requirements while maintaining reliable signal processing.
2Object-affected harmful factors
If the receiver uses traditional filtering approaches to remove interference, then interference attenuation can be achieved, but inband signal attenuation (droop) increases
Solution Approach 1:
The patent applies local quality by designing a bandpass filter with specific frequency characteristics that selectively attenuates interference components while preserving inband signal components. The filter is configured with a passband centered on the desired signal frequency and stopbands targeting interference frequencies, achieving localized frequency-selective filtering that distinguishes between harmful interference and useful signal.
3Measurement precision
If the receiver increases the linearity and filtering capabilities of downstream processing blocks, then signal processing accuracy improves, but power consumption and cost increase
Solution Approach 1:
The patent reduces power consumption by performing interference filtering upstream before the mixer and baseband processing blocks. This preliminary action removes interference components that would otherwise require high linearity and filtering capabilities in downstream blocks, allowing these blocks to operate with lower specifications and reduced power consumption while maintaining signal processing accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The LC notch filter effectively reduces interference, minimizing inband droop and simplifying downstream processing blocks, leading to reduced power consumption and cost in radio frequency receivers while maintaining signal quality.
Implementation Method 1
The LC based notch filter is arranged to receive the down-converted signal from the mixer, filter the down-converted signal, and output the filtered signal for processing by a baseband processing block. The LC based notch filter has a notch centered within the interference frequency range, such that the LC based notch filter is arranged to attenuate the interference component in the down-converted signal.
Data Source
AI summary
Circuitry and a method for use in a radio frequency receiver for processing a radio frequency signal are provided. The circuitry comprises a mixer arranged to receive the radio frequency signal and down-convert the received radio frequency signal to a lower frequency. The received radio frequency signal has an interference component and the interference component in the down-converted signal is within an interference frequency range. The circuitry also comprises an LC based notch filter arranged to receive the down-converted signal from the mixer, filter the down-converted signal, and output the filtered signal for processing by a baseband processing block. The LC based notch filter has a notch centered within said interference frequency range, such that the LC based notch filter is arranged to attenuate the interference component in the down-converted signal.