Tunable Notch Filter Reduces Tx Leakage via Feedback Receiver
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Solution Overview
Problem
Existing wireless communication devices face challenges in reducing transmit (Tx) leakage signals in received signals due to the limited capabilities of non-adaptive filters, which affect signal quality and require innovative solutions to adapt to varying conditions.
Innovation Solution
A tunable notch filter system using feedback through an existing envelope tracking (ET) receiver, incorporating a transceiver chip with a Tx leakage signal reduction module that includes a notch filter and a feedback receiver to minimize Tx leakage by adjusting impedance and filtering out interference across process, voltage, and temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-adaptive filters are used to remove transmit leakage signals, then the device structure is simple, but the signal quality is poor and the frequency band coverage is limited
Solution Approach 1:
The patent implements an adaptive filter system where filter coefficients are dynamically adjusted based on feedback from the received signal. The system continuously monitors the leakage signal characteristics and adapts the filter parameters in real-time, transforming a static non-adaptive filter into a dynamic adaptive filter that maintains optimal performance across varying conditions.
Solution Approach 2:
The patent employs a feedback mechanism where the received signal is fed back to the adaptive filter controller, which processes the signal and adjusts the filter coefficients accordingly. This closed-loop feedback system enables the filter to learn and adapt to the actual leakage signal characteristics, improving signal quality while managing device complexity through intelligent control.
2Reliability
If adaptive filters are used to adapt to leakage signals, then signal quality improves, but device complexity increases
Solution Approach 1:
The patent designs the adaptive filter system to perform multiple functions: it not only removes transmit leakage signals but also adapts to varying frequency bands, adjusts to different signal conditions, and maintains performance across process, voltage, and temperature variations. This multi-functional approach consolidates what would otherwise require multiple separate components into a single adaptive filtering system.
Solution Approach 2:
The patent utilizes variable capacitors and adjustable impedance elements that can change their electrical parameters dynamically. By modifying capacitance values and impedance levels based on feedback signals, the system adapts its filtering characteristics without requiring physical reconfiguration, thereby managing complexity through electrical parameter adjustment rather than mechanical or structural changes.
3Reliability
If external diversity surface acoustic wave filters are added to reduce Tx leakage, then signal quality improves, but device size, cost, and power consumption increase
Solution Approach 1:
The patent integrates the Tx leakage reduction functionality directly into the existing receiver chain by placing the adaptive filter in the signal path between the low noise amplifier and the mixer. This merging of functions eliminates the need for separate external diversity surface acoustic wave filters, as the adaptive filtering is performed within the main receiver architecture using shared components.
Solution Approach 2:
The adaptive filter system is self-configuring and self-adjusting, using feedback from the received signal to automatically tune its parameters. This self-service capability eliminates the need for external calibration equipment or additional control circuits that would be required for external filters, thereby reducing device size, cost, and power consumption while maintaining effective Tx leakage reduction.
Data Source
AI summary
A wireless communication device configured for reducing Tx leakage in a receive signal is described. The wireless communication device includes a transceiver chip. The transceiver chip includes a receiver, a feedback receiver and a transmitter. The wireless communication device also includes a Tx leakage signal reduction module. The Tx leakage signal reduction module reuses the feedback receiver.