OZIF Baseband Filter Circuit for Non-Contiguous Carrier Aggregation
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Solution Overview
Problem
Current mobile RF transceivers face design complexities and performance issues, particularly with non-contiguous carrier aggregation, due to noise at harmonic frequencies and limitations in jammer frequency filtering, leading to reduced signal-to-noise ratio and inability to adjust gains independently across different bandwidth combinations.
Innovation Solution
A radio frequency baseband filter circuit with offset zero intermediate frequency (OZIF) technology, incorporating two complex baseband filters and a combiner, allows independent gain adjustment of different bandwidth combinations while filtering out jammers, reducing current consumption and supporting flexible gain control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional jammer frequency filtering is used in mobile RF transceivers, then noise at harmonic frequencies can be reduced, but the signal-to-noise ratio deteriorates and independent gain adjustment across different bandwidth combinations becomes impossible
Solution Approach 1:
The baseband filter is divided into multiple independent complex filter banks, each handling specific frequency bands. This segmentation allows selective filtering of jammer frequencies while preserving signal quality in other bands, enabling independent gain adjustment for different bandwidth combinations without degrading overall signal-to-noise ratio
Solution Approach 2:
The filter implements dynamic gain control where each filter bank can independently adjust its gain based on the specific bandwidth combination being used. This dynamic adaptation allows the system to optimize performance for different carrier aggregation scenarios while maintaining signal integrity and filtering harmful frequencies selectively
2Productivity
If carrier aggregation is implemented to increase bandwidth, then data transmission capacity is improved, but design complexity and noise at harmonic frequencies increase
Solution Approach 1:
The filter circuit is designed with multiple filter banks that can be selectively activated based on the carrier aggregation configuration. This universal design allows the same hardware structure to handle various bandwidth combinations and frequency arrangements, reducing design complexity while supporting enhanced data transmission capacity through carrier aggregation
Solution Approach 2:
The system dynamically changes filter parameters such as center frequencies, bandwidths, and gain values based on the active carrier aggregation configuration. This parameter adaptation enables the filter to efficiently handle multiple frequency combinations without requiring separate dedicated filters for each scenario, thereby managing design complexity while supporting increased data capacity
3Quantity of substance
If multiple frequencies are used simultaneously for carrier aggregation, then bandwidth is increased, but noise at harmonic frequencies and interference from jammers worsen
Solution Approach 1:
Each filter bank is designed with specific local characteristics tailored to its assigned frequency range, including optimized center frequencies, bandwidths, and Q-factors. This local quality optimization allows effective suppression of harmonic noise and jammer interference in specific frequency regions while maintaining high signal quality in other bands, enabling increased bandwidth utilization without proportionally increasing harmful interference
Data Source
AI summary
A filter circuit may include a first path having a first complex baseband filter. The circuit may further include a second path having a second complex baseband filter. The circuit may further include a combiner coupled to an output of the first complex baseband filter and an output of the second complex baseband filter.