Parallel Filter Circuit Path for Attenuation
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Solution Overview
Problem
Existing filter circuits in mobile devices face challenges in increasing attenuation in specific frequency bands outside the passband without incurring significant insertion loss, particularly when using phase shifters in series.
Innovation Solution
A filter circuit design that includes a path connected in parallel with the filter part, where the impedance of this path allows a first signal to have an opposite phase relationship and equal amplitude to a second signal in frequency bands outside the passband, effectively attenuating signals by combining these signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a phase shifter is connected in series to the filter to increase attenuation in a particular frequency band outside the passband, then the attenuation in that frequency band is improved, but the insertion loss increases
Solution Approach 1:
The invention divides the filter circuit into two parallel paths: a filter path (containing the filter) and a bypass path (containing the phase shifter). This segmentation allows the phase shifter to operate independently in parallel rather than in series, enabling selective signal routing that achieves attenuation in specific frequency bands without forcing all signals through the phase shifter, thereby reducing overall insertion loss.
Solution Approach 2:
The invention introduces a switching mechanism as an intermediary between the filter path and bypass path. This switch acts as a mediator that dynamically routes signals based on frequency band requirements, allowing the system to achieve attenuation when needed while maintaining low insertion loss when the phase shifter is not required, thus resolving the contradiction between attenuation performance and energy efficiency.
2Object-affected harmful factors
If a phase shifter is connected in series to the filter to increase attenuation, then the attenuation characteristic is improved, but the device complexity increases
Solution Approach 1:
By segmenting the circuit into parallel filter and bypass paths, the phase shifter becomes a separate modular component rather than being integrated in series. This modular segmentation makes the circuit easier to design, implement, and adjust, as each path can be independently optimized and the overall structure is more transparent.
Solution Approach 2:
The invention employs a dynamic switching mechanism that adapts the circuit configuration based on the required frequency band. This dynamic element allows the system to simplify its operation by bypassing the phase shifter when not needed, effectively reducing the active complexity only when attenuation is required, rather than maintaining maximum complexity continuously.
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
This design achieves increased attenuation in frequency bands outside the passband while maintaining low insertion loss, allowing for flexible adjustment of attenuation characteristics.
Implementation Method 1
the path having an impedance that enables a first signal passing through the path from the input terminal to the output terminal and a second signal passing through the filter part from the input terminal to the output terminal to have an opposite phase relationship in a frequency band outside of the passband
Data Source
AI summary
A filter circuit includes a filter part connected between an input terminal and an output terminal and configured to have a passband, and a path connected in parallel with the filter part between the input terminal and the output terminal, the path having an impedance that enables a first signal passing through the path from the input terminal to the output terminal and a second signal passing through the filter part from the input terminal to the output terminal to have an opposite phase relationship in a frequency band outside of the passband and have almost equal amplitudes in the frequency band.