Duplexer Interference Cancellation via Phase-Adjusted Signal Segmentation
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Solution Overview
Problem
Traditional small filters in radio communication systems fail to meet the strict suppression requirements for duplexers, leading to interference issues due to outband amplitude and phase response fluctuations, which are not effectively cancelled by existing interference cancellation methods.
Innovation Solution
The method involves using a coupler to divide a transmitted signal into two parts, with one part input into a first receiving filter and the other into a duplexer with integrated receiving and transmitting filters, where the interfering signals are adjusted to opposite phases and combined to cancel interference, ensuring consistent electric performance between symmetric filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional small filters are used to reduce duplexer size, then the size of the communication system is reduced, but the suppression requirement cannot be fulfilled due to outband amplitude and phase response fluctuations
Solution Approach 1:
The transmitted signal is divided into two parts by a coupler: one part enters the receiving filter directly, while the other part passes through a transmitting filter first. This segmentation allows the system to handle different signal paths separately, enabling interference cancellation through phase adjustment and combination of the two paths.
Solution Approach 2:
The patent converts the harmful outband amplitude and phase response fluctuations of the transmitting filter into a beneficial effect. By intentionally passing one signal path through the transmitting filter and then adjusting the phase of this path, the system uses the filter's characteristics to generate an interference signal that, when combined with the direct path signal, cancels out the unwanted interference in the receiving band.
2Ease of operation
If interference cancellation is implemented using amplitude phase regulator, then the phase adjustment is performed, but the interference is not cancelled effectively because the receiving filter response is relatively constant while the transmitting filter outband response fluctuates sharply
Solution Approach 1:
The patent introduces dynamic phase adjustment through a phase regulator that can adaptively change the phase of the signal path that passed through the transmitting filter. This dynamic adjustment compensates for the outband phase fluctuations of the transmitting filter, ensuring that the combined signal achieves effective interference cancellation in the receiving band.
Solution Approach 2:
The system implements a feedback mechanism where the signal path through the transmitting filter is monitored and adjusted via the phase regulator to achieve the desired interference cancellation effect. The phase adjustment is optimized based on the actual interference conditions, creating a closed-loop control system that adapts to varying signal conditions.
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 approach effectively cancels interfering signals leaked to the receiving channel, reducing interference and meeting the stringent suppression requirements, thereby enabling smaller and more efficient duplexer designs.
Implementation Method 1
The FBAR is a duplexer based on a bulk acoustic resonance technology, and converts the electric energy into acoustic waves to generate resonance through a converse piezoelectric effect of a piezoelectric film
Implementation Method 2
using a coupler to divide a transmitted signal into two parts, with one part input into a first receiving filter and the other into a duplexer
Implementation Method 3
the interfering signals are adjusted to opposite phases and combined to cancel interference
Data Source
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AI summary
An interference cancellation method and apparatus and also a filter are disclosed to cancel the interfering signals leaked to the receiving channel, and enable the receiving channel to suppress the transmitted signal. The method includes: dividing a transmitted signal into a first transmitted signal and a second transmitted signal, and then inputting the first transmitted signal into a first transmitting filter and inputting the second transmitted signal into a second transmitting filter symmetric to the first transmitting filter; adjusting the first interfering signal and the second interfering signal to make opposite phases of the signals; and combining the signals of opposite phases. The method provided herein can cancel the interfering signals leaked to the receiving channel, the receiving channel suppresses the transmitted signal effectively, and the interference caused by the transmitted signal onto the received signal is cancelled.