Switchable Filter Circuit for Tx/Rx Space Reduction
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Solution Overview
Problem
Conventional wireless transceiver systems require two independent filters for receiving and transmitting modes, leading to increased space and cost due to the need for separate filtering circuits.
Innovation Solution
A filtering device with a capacitive and resistive circuit that switches between two configurations to perform either band-pass or low-pass filtering processes, using a single differential amplifier and minimizing the number of required filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two independent filters are installed for receiving and transmitting modes, then the filtering performance is improved, but the area and cost increase
Solution Approach 1:
The patent applies multi-functionality by designing a single filter circuit that can perform both receiving-mode filtering and transmitting-mode filtering through configuration switching. The filter is controlled by a control signal that switches between first and second configurations, allowing one filter to replace what would traditionally require two separate filters, thereby reducing circuit area while maintaining filtering performance
Solution Approach 2:
The patent implements dynamics by making the filter configuration switchable based on operational mode. The filter transitions between a first configuration (with first capacitive and resistive configurations) for receiving mode and a second configuration (with second capacitive and resistive configurations) for transmitting mode, allowing the same hardware to adapt its characteristics dynamically rather than being fixed
2Reliability
If two independent filters are installed for receiving and transmitting modes, then the filtering performance is improved, but the cost increases
Solution Approach 1:
The patent reduces manufacturing cost by designing a universal filter circuit that serves dual purposes. Instead of manufacturing and stocking two separate filter components, the system uses one filter with switchable configurations controlled by mode signals, simplifying the supply chain and reducing component costs while maintaining the required filtering performance for both transmitting and receiving modes
3Area of stationary object
If a single filter is used for both receiving and transmitting modes, then the area and cost are reduced, but the filtering performance may be compromised
Solution Approach 1:
The patent resolves the performance concern by making the filter dynamic rather than static. The filter configuration is switched based on the operational mode: in receiving mode, the first capacitive and resistive configurations provide appropriate filtering characteristics, while in transmitting mode, the second capacitive and resistive configurations provide different characteristics optimized for transmission, ensuring high filtering performance in both modes with a single filter
Data Source
AI summary
A filtering device, applicable in a transceiver, includes: a capacitive circuit coupled to an amplifying circuit by a first capacitive configuration or by a second capacitive configuration; and a resistive circuit coupled to the amplifying circuit by a first resistive configuration or by a second resistive configuration; wherein when the capacitive circuit is the first capacitive configuration, the filtering device is used to perform a first filtering process upon a receiving signal of the filtering device, and when the capacitive circuit is the second capacitive configuration, the filtering device is used to perform a second filtering process upon a transmitting signal of the filtering device.