Baseband Filter Bandwidth Adjustment for DC Offset Correction
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Solution Overview
Problem
Radio devices face challenges in rapidly correcting DC offset within the limited time slot of a radio communication system, as existing solutions are either complex, occupy significant space, or have delayed response times due to bandwidth limitations and voltage-dependent filter reset times.
Innovation Solution
The apparatus employs one or two-stage signal-processing units with a baseband filter, gain stage, and a DC offset correction loop, utilizing a bandwidth-controlling unit, capacitor section, and operational amplifier to rapidly adjust the bandwidth of the baseband filter by pre-charging a capacitor to a preset voltage, allowing for quick DC offset correction and reducing occupied area and component cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a DC offset correction loop is implemented with sequential comparison and standard baseband filter, then DC offset correction capability is provided, but the response time is delayed due to bandwidth limitations and filter reset time dependencies
Solution Approach 1:
The patent applies preliminary action by pre-charging the capacitor to a preset voltage level before the DC offset correction process begins. This preliminary charging action eliminates the need for waiting during filter reset, allowing the baseband filter to immediately operate at the required bandwidth for rapid DC offset correction, thus reducing the overall response time while maintaining correction capability
Solution Approach 2:
The patent implements dynamics by making the baseband filter bandwidth adjustable through capacitor charging states. The filter can dynamically switch between normal operational bandwidth and a wider bandwidth mode during DC offset correction, allowing the system to adapt its filtering characteristics to the immediate correction needs rather than being constrained by fixed bandwidth limitations
2Reliability
If existing DC offset correction solutions are implemented, then DC offset correction function is achieved, but the device complexity and occupied area increase
Solution Approach 1:
The patent applies universality by designing a circuit where the same capacitor and switching components serve multiple functions: they control baseband filter bandwidth adjustment, enable DC offset correction, and reduce settle time. This multi-functional approach eliminates the need for separate dedicated components for each function, thereby reducing overall device complexity while maintaining complete DC offset correction capability
Solution Approach 2:
The patent utilizes parameter changes by adjusting the voltage potential of the capacitor to control the baseband filter's 3dB corner frequency. By changing the capacitor voltage from discharged to preset levels, the system dynamically modifies filter bandwidth without requiring complex mechanical or structural changes, providing a simple and efficient way to reduce device complexity while achieving the correction function
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 enables rapid DC offset correction within the allotted time slot, reducing settle time and maintaining operational efficiency while simplifying the configuration and minimizing space and cost.
Implementation Method 1
a capacitor section, a resistor section and an operational amplifier. A connection direction of an electrode terminal of a capacitor disposed within the capacitor section is capable of being switched by the controller to process a pre-charge or discharge phases
Data Source
AI summary
The instant invention relates to an apparatus and method for enhancing DC offset correction speed of a radio device. On the exemplary, the apparatus includes one or two-stage signal-processing units and a controller. Each signal-processing unit has a baseband filter, a gain stage and a DC offset correction (DCOC) loop applied on the gain stage. A connection direction of an electrode terminal of a capacitor of the baseband filter is capable of being switched by the controller to process a pre-charge or a discharge phases thereby adjusting a bandwidth of the baseband filter to be either a normal operational bandwidth or wider than the normal operational bandwidth for rapidly setting time of the baseband filter.