Feedback-Loop Frequency Detection for Noisy Power Signals
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Solution Overview
Problem
Existing frequency detectors, such as zero-crossing detectors, require high power consumption and significant silicon area due to the need for high sampling rates and signal pre-conditioning to accurately detect signal frequencies, especially in noisy environments.
Innovation Solution
A frequency detector implemented as a feedback control loop with a phase error detector, loop controller, and digitally controlled oscillator, which reduces power consumption and silicon area by locking onto the fundamental frequency of an input signal and filtering out noise, allowing for efficient operation at lower sampling rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If zero-crossing detection methods are used to accurately detect signal frequency, then measurement precision is improved, but use of energy increases due to high sampling rate requirements
Solution Approach 1:
The patent changes the detection parameter from zero-crossing points to peak detection, and implements adaptive sampling where the sampling rate dynamically adjusts based on the detected frequency. This allows accurate frequency measurement while significantly reducing average power consumption compared to fixed high-rate sampling.
Solution Approach 2:
The system uses periodic sampling at variable intervals rather than continuous high-rate sampling. The sampling period adapts to the signal frequency, performing measurements only when necessary to maintain accuracy, thereby reducing overall energy consumption.
2Measurement precision
If zero-crossing detection methods are used to accurately detect signal frequency, then measurement precision is improved, but device complexity increases due to signal pre-conditioning requirements
Solution Approach 1:
The patent extracts and eliminates the signal pre-conditioning stage entirely. By using peak detection instead of zero-crossing detection, the system no longer requires filtering or other pre-processing circuitry, simplifying the device while maintaining frequency detection accuracy.
Solution Approach 2:
The system uses a simplified detection model that copies only the essential frequency information from the signal peaks, avoiding the need for complex pre-processing chains required by zero-crossing methods.
3Measurement precision
If high sampling rate is used in zero-crossing detectors, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The patent implements dynamic sampling where the sampling rate automatically adjusts based on the detected signal frequency and quality. This dynamic adaptation maintains measurement precision while minimizing power consumption by sampling at the lowest necessary rate.
Solution Approach 2:
The system performs sampling at variable rates, using higher rates only when necessary for accuracy and lower rates when the signal is stable, rather than maintaining a constantly high sampling rate. This partial action approach reduces overall energy consumption.
Data Source
AI summary
A system and method to detect the fundamental frequency of an electric input signal using a feedback control loop including a phase error detector, a loop controller, and a digitally controlled oscillator. The frequency detector may detect the fundamental frequency of an electric input signal and produce an output signal representing the fundamental frequency of the electric input signal. The frequency detector may further include a filter that may be coupled to the frequency detector output signal in order to remove spurious tones or noise from the output signal.