Single-Ended Receiver Filtering Out-of-Band Blockers Without SAW
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Solution Overview
Problem
Conventional receivers face challenges in maintaining linearity and reducing power consumption due to high out-of-band blockers, which require external SAW filters or baluns, making them costly and unsuitable for modern cellular bands with multiple input ports, especially when trying to save manufacturing costs and improve GSM, GPRS, and EDGE sensitivity.
Innovation Solution
A receiver design that includes an input node, a blocker detector, and a translational filter, which dynamically filters out-of-band blockers based on detection results, allowing a low-noise amplifier to operate without external filters or baluns, using a single-ended configuration and lower supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external SAW filter is used to reject out-of-band blockers, then linearity is improved, but manufacturing cost increases and device complexity increases
Solution Approach 1:
The patent combines the blocker detection function and filtering function into the receiver itself. The blocker detector monitors for out-of-band blockers and controls the translational filter accordingly, merging what were previously separate external components (SAW filter) and control systems into an integrated solution that eliminates the need for external filtering hardware.
Solution Approach 2:
The receiver performs its own blocker detection and filtering operations autonomously. The blocker detector continuously monitors the input signal for blockers, and the translational filter is automatically controlled based on detection results, allowing the receiver to self-manage its signal conditioning without requiring external passive filtering components.
2Reliability
If external balun is used to provide differential input signal and out-of-band blockers rejection, then linearity is improved, but device complexity increases and manufacturing cost increases
Solution Approach 1:
The patent integrates the balun functionality and blocker rejection capability into the receiver's input stage. The single-ended to differential conversion is performed within the receiver, and the blocker detection and filtering are coordinated with the input signal processing, eliminating the need for a separate external balun component.
Solution Approach 2:
The receiver's input stage is designed to perform multiple functions: single-ended to differential conversion, blocker detection, and signal amplification. This multi-functional design replaces what would traditionally require separate external components (balun, SAW filter, LNA), reducing overall system complexity.
3Reliability
If supply voltage is enlarged to tolerate out-of-band blockers, then linearity is improved, but power consumption increases
Solution Approach 1:
The translational filter is activated in advance to remove out-of-band blockers before the signal reaches the low-noise amplifier. By pre-filtering the input signal, the LNA can operate at lower supply voltages without being overwhelmed by strong blockers, thus reducing power consumption while maintaining linearity.
Solution Approach 2:
The translational filter acts as an intermediary component between the antenna and the LNA. It selectively removes harmful out-of-band frequencies while passing the desired signal band, enabling the LNA to operate in a cleaner signal environment with reduced power requirements.
4Ease of manufacture
If SAW filter is removed to save manufacturing cost, then manufacturing cost is reduced, but linearity deteriorates due to out-of-band blockers
Solution Approach 1:
The receiver performs its own blocker detection and filtering operations autonomously. The blocker detector continuously monitors the input signal for blockers, and the translational filter is automatically controlled based on detection results, allowing the receiver to self-manage its signal conditioning without requiring external passive filtering components.
Solution Approach 2:
The system dynamically changes its operating parameters based on detected blocker conditions. When blockers are detected, the translational filter is activated with specific frequency translation parameters to remove the blockers. This adaptive parameter control allows the system to maintain linearity only when needed, rather than always requiring expensive external filtering hardware.
Data Source
AI summary
The present invention provides a receiver having an input node, a blocker detector, a translational filter and a low-noise amplifier. The input node is arranged to receive an input signal. The blocker detector is configured to detect if the input signal has a blocker to generate a detection result. The translational filter is configured to filter out an output-of-band blocker of the input signal to generate a filtered input signal at the input node or not filter output the output-of-band blocker of the input signal according to the detection result. The low-noise amplifier is configured to receive the filtered input signal or the input signal to generate an amplified input signal.