Digitally Controlled Analog RF Hybrid Filter for Low-Noise Adaptation
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Solution Overview
Problem
Digital filters introduce noise and processing delays, and require high-speed Analog-to-Digital Converters (ADCs) and Digital to Analog Converters (DACs), making them unsuitable for all applications, especially those requiring flexible and low-noise filtering.
Innovation Solution
A digitally controlled analog filter device that uses digitally controlled analog signal amplifiers and time delay circuits, with digital closed-loop control to adjust gain and delay, quantizing only coefficients rather than the signal, thereby minimizing noise and delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If digital filters are used to implement filtering functionality, then filtering flexibility and controllability are improved, but quantization noise floor increases and processing delays are introduced
Solution Approach 1:
The system segments the filtering function into two parts: digital control signals that set filter parameters (coefficients) and analog processing that performs the actual filtering. This allows the beneficial analog processing to occur on the full-precision signal while digital control provides flexibility.
Solution Approach 2:
Digital control signals act as intermediaries between the digital control system and the analog filter. The digital signals control analog switches and variable components to adjust filter characteristics without directly processing the audio signal, thus avoiding quantization noise.
2Adaptability or versatility
If digital filters are used to implement filtering functionality, then filtering flexibility and controllability are improved, but processing delays increase
Solution Approach 1:
The system separates control functions (digital) from signal processing functions (analog). Digital control signals adjust filter parameters instantaneously through analog switches and variable components, eliminating the multi-cycle processing delays inherent in digital filter computations.
Solution Approach 2:
The patent replaces digital signal processing operations with analog circuit operations. Analog filters process signals continuously in real-time without the discrete sampling and computational delays characteristic of digital systems.
3Object-generated harmful factors
If analog filters are used to implement filtering functionality, then noise floor is reduced and processing is faster, but filtering flexibility and digital controllability are limited
Solution Approach 1:
The analog filter incorporates dynamically controllable elements such as analog switches and variable components whose characteristics can be changed in real-time. Digital control signals dynamically adjust these analog parameters to achieve different filter configurations and responses.
Solution Approach 2:
Digital control signals serve as intermediaries that translate digital control commands into analog parameter adjustments. These digital signals control analog switches, variable resistors, or other programmable analog components to reconfigure the filter without compromising signal quality.
4Measurement precision
If digital filters are used to implement filtering functionality, then filtering precision is improved, but high-speed ADCs and DACs are required increasing device complexity
Solution Approach 1:
The system divides the signal processing chain into digital control (for precision parameter setting) and analog processing (for high-speed full-precision signal manipulation). This segmentation eliminates the need for high-speed ADCs and DACs in the signal path while maintaining filtering precision through accurate digital control of analog parameters.
Solution Approach 2:
The patent uses digital control signals as a copy or representation of the desired filter characteristics. These digital control values are converted to analog parameters that directly control the filter behavior, avoiding the need to digitize and process the entire audio signal.
Data Source
AI summary
A digitally controlled analog filter device. The digitally controlled analog filter device includes one or more digitally controlled analog signal amplifiers. The digitally controlled analog signal amplifiers are configured to have a gain of the digitally controlled analog signal amplifiers controlled by digital signals. The digitally controlled analog filter device further includes one or more analog time delay circuits coupled to signal input nodes of the digitally controlled analog signal amplifiers. The analog time delay circuits are configured to implement an analog signal delay. The digitally controlled analog filter device further includes a digital closed loop control circuit coupled to the digitally controlled analog signal amplifiers to digitally control the gain of the digitally controlled analog signal amplifiers.