Successive-Window Notch Filter for Low-Power RF Selectivity
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Solution Overview
Problem
Existing electronic band-pass filtering devices face limitations in power consumption and selectivity due to the use of N-path filters, which require high clock frequencies and complex architectures, leading to increased power consumption and reduced maximum operating frequency.
Innovation Solution
An electronic notch filter and band-pass filtering device that integrates the input signal during multiple successive time windows with a summing module to generate a filtered signal, reducing power consumption while maintaining high selectivity, and eliminates the need for input splitters and output combiners by using two distinct notch filters with different cutoff frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If N-path filters are used to achieve high rejection and selectivity, then filtering performance is improved, but power consumption increases and maximum operating frequency decreases
Solution Approach 1:
The patent extracts and eliminates the clocking mechanism from the filtering operation. By using a continuous-time filter without requiring high-frequency clocks to subdivide the signal period, the design removes the primary source of power consumption while maintaining filtering selectivity through the continuous integration process
Solution Approach 2:
The patent replaces the mechanical switching operation of N-path filters with an electronic continuous integration approach. Instead of using switches to sample and hold signal portions at different phases, the invention uses a continuous integrator that processes the signal without mechanical switching, thereby eliminating the associated power consumption and frequency limitations
2Measurement precision
If N-path filters are used to achieve high rejection, then filtering performance is improved, but device complexity increases due to input splitters and output combiners
Solution Approach 1:
The patent extracts and removes the input splitter and output combiner components from the filter architecture. By using a single continuous integrator that directly processes the input signal and produces the output, the design eliminates the complex multi-path switching network and associated components while achieving comparable or superior rejection performance
Solution Approach 2:
The patent merges the functions of multiple N-path filters into a single continuous-time filter. Instead of requiring separate filters for different frequency paths with complex combining logic, the invention uses one integrator that handles all frequency components continuously, thereby simplifying the overall architecture while maintaining high rejection
3Measurement precision
If the order of N-path filter is increased to improve selectivity, then filtering selectivity is improved, but power consumption increases and operating frequency is limited
Solution Approach 1:
The patent implements a dynamic integration window approach where the integration duration can be adjusted to achieve the desired selectivity. By varying the integration time constant rather than increasing filter order, the system maintains high selectivity while allowing continuous operation at high throughput rates without the power consumption and frequency limitations associated with higher-order N-path filters
Data Source
AI summary
This electronic notch filter is able to receive an input signal and deliver a filtered signal having an amplitude, at a cut-off frequency, that is attenuated with respect to that of the input signal.It comprises a module for integrating the input signal during several successive time windows, each time window starting at a respective initial time instant and having a duration substantially equal to the inverse of the cut-off frequency, the initial temporal time instants of at least two distinct windows being separated by a temporal shift of a value greater than or equal to a predefined reference duration, each integration of the input signal during a respective temporal window resulting in a respective intermediate signal; and a module for summing the intermediate signals coming from the integration module; the filtered signal depending on the sum of said intermediate signals.