Feedback Circuit Phase Measurement Using Hilbert Transform
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Solution Overview
Problem
Negative feedback circuits with semiconductor-based resistors and capacitors exhibit large parameter variations, leading to narrow bandwidths and slow response times, which result in significant output voltage fluctuations when load current changes, and direct conversion methods for measuring circuit characteristics are prone to accuracy issues due to temperature variations and analog circuit instability.
Innovation Solution
An electronic circuit employing AD converters and phase adjustors using Hilbert transforms to accurately adjust phases and perform direct conversion, allowing for precise measurement of gain and phase characteristics, thereby enabling adjustable feedback circuit characteristics for improved stability and response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a negative feedback circuit is designed with narrow bandwidth to ensure stability despite parameter variations, then stability is improved, but response time becomes slow and convergence takes longer
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the bandwidth of the negative feedback circuit based on operating conditions. The control unit modifies feedback circuit parameters in real-time to achieve optimal balance between stability and response speed, rather than fixing the bandwidth to a narrow value for all conditions.
Solution Approach 2:
The invention implements dynamics by making the feedback circuit adaptive and configurable. The bandwidth and other parameters are not fixed but can be dynamically adjusted according to load conditions and operational requirements, allowing the system to transition between stability-oriented and speed-oriented modes as needed.
2Reliability
If a negative feedback circuit uses narrow bandwidth to ensure stability, then stability is improved, but output voltage fluctuation increases in response to sudden load current changes
Solution Approach 1:
The control unit dynamically adjusts feedback circuit parameters based on load current changes. When sudden load changes are detected, the system modifies parameters to reduce output voltage fluctuation while maintaining stability, preventing the harmful effects of fixed narrow bandwidth design.
3Difficulty of detecting and measuring
If direct conversion is used to measure gain characteristics, then measurement capability is achieved, but phase displacement accuracy deteriorates due to difficulty in providing 90-degree phase displacement
Solution Approach 1:
The patent replaces the analog phase-shifting mechanism with a digital signal processing approach. Instead of using analog circuits to achieve 90-degree phase displacement, the system uses digital signal processing to calculate and determine phase differences, thereby achieving high measurement precision without the limitations of analog phase shifters.
Solution Approach 2:
The invention introduces a control unit as an intermediary between signal generation and measurement. This control unit performs digital signal processing to accurately determine phase differences, acting as a mediator that eliminates the need for precise analog phase displacement while enabling accurate measurement.
4Speed
If analog circuits are used to implement AFE, mixer circuit, and low-pass filter for direct conversion, then high-frequency signal processing is achieved, but circuit characteristic variation increases due to temperature changes and deterioration
Solution Approach 1:
The patent replaces analog signal processing circuits (AFE, mixer, low-pass filter) with digital signal processing implemented in a control unit. This substitution eliminates the temperature sensitivity and deterioration issues of analog circuits while maintaining the ability to process signals at required speeds through efficient digital algorithms.
Solution Approach 2:
The invention uses digital copies and representations of signals rather than direct analog processing. By converting signals to digital form and processing them computationally, the system achieves signal processing functionality without relying on temperature-sensitive analog circuit characteristics.
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 solution enables high-precision measurement and adjustment of circuit characteristics, reducing output voltage fluctuations and improving response speed by stabilizing the feedback circuit and accurately adjusting phase and amplitude measurements.
Implementation Method 1
at least one first phase adjustor configured to adjust a phase of the digital oscillating signal through the Hilbert transform to produce an output, a second phase adjustor configured to adjust a phase of the digital input signal through the Hilbert transform to produce an output
Implementation Method 2
a first mixer circuit configured to multiply the output of the first phase adjustor and the output of the second phase adjustor, and a second mixer circuit configured to multiply the output of the first phase adjustor and the output of the third phase adjustor
Data Source
AI summary
An electronic circuit includes a circuit to receive an analog input signal responsive to an analog oscillating signal and to generate an analog output signal, AD converters to perform AD-conversion with respect to the analog oscillating signal, the analog input signal, and the analog output signal to generate a digital oscillating signal, a digital input signal, and a digital output signal, at least one first adjustor to adjust a phase of the digital oscillating signal through the Hilbert transform, a second adjustor to adjust a phase of the digital input signal through the Hilbert transform, a third adjustor to adjust a phase of the digital output signal through the Hilbert transform, a first mixer circuit to multiply the output of the first adjustor and the output of the second adjustor, and a second mixer circuit to multiply the output of the first adjustor and the output of the third adjustor.