Fractional Peak Discriminator Circuit for Adaptive Speed Sensing
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Solution Overview
Problem
Existing methods for sensing rotational speed, such as optical and magnetic tachometers, face challenges in maintaining signal integrity due to noise and varying light or magnetic field conditions, requiring manual adjustments and being prone to errors from dirt, fading, or changes in the optical path.
Innovation Solution
A signal conditioner circuit that includes a filter, peak detector, peak divider, and comparator to generate a pulse when the filtered signal exceeds a predetermined fraction of the peak signal, automatically adjusting for changing signal levels and reducing noise interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical or magnetic sensing methods are used to detect rotational speed, then the ability to detect speed is improved, but the system becomes sensitive to noise and signal level variations
Solution Approach 1:
The circuit dynamically adjusts the reference voltage level by detecting the peak amplitude of each signal cycle and using it to set the threshold for the next cycle. This dynamic adaptation allows the circuit to maintain reliable operation despite variations in signal amplitude caused by changes in rotational speed, lighting conditions, or magnetic field strength.
Solution Approach 2:
The circuit automatically calibrates itself by using the incoming signal's own peak amplitude to generate the reference voltage threshold. This self-service mechanism eliminates the need for external manual calibration or fixed reference voltages, allowing the system to adapt autonomously to changing operating conditions while maintaining noise rejection capabilities.
2Device complexity
If a fixed threshold comparator is used to generate output pulses, then the circuit simplicity is improved, but the system requires manual adjustments and is prone to errors from changing signal levels
Solution Approach 1:
The circuit automatically calibrates itself by using the incoming signal's own peak amplitude to generate the reference voltage threshold. This self-service mechanism eliminates the need for external manual calibration or fixed reference voltages, allowing the system to adapt autonomously to changing operating conditions while maintaining noise rejection capabilities.
Solution Approach 2:
The peak detector continuously monitors the signal amplitude and feeds back this information to adjust the reference voltage threshold. This feedback loop ensures that the comparator threshold automatically tracks with signal level variations, maintaining reliable pulse generation without requiring manual intervention or complex external control systems.
3Adaptability or versatility
If the signal level decreases due to increased speed or environmental factors, then the measurement range is improved, but the signal becomes more susceptible to noise filtering
Solution Approach 1:
The circuit dynamically adjusts the reference voltage level by detecting the peak amplitude of each signal cycle and using it to set the threshold for the next cycle. This dynamic adaptation allows the circuit to maintain reliable operation despite variations in signal amplitude caused by changes in rotational speed, lighting conditions, or magnetic field strength.
Solution Approach 2:
The reference voltage parameter is automatically changed based on the detected signal peak amplitude. By scaling the threshold proportionally with the signal level, the circuit maintains optimal detection sensitivity across a wide range of operating conditions, preventing both false positives from noise and false negatives from weak signals.
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
The circuit effectively senses rotational speed by generating a reliable output pulse, adapting to variations in signal amplitude and frequency, while minimizing false triggers from noise, thus improving the robustness and accuracy of rotational speed measurement systems.
Implementation Method 1
a filter for receiving an electrical signal generated by a sensor; said filter for generating a filtered signal
Implementation Method 2
a peak detector configured to receive said filtered signal and to detect said peak and generate a detected-peak signal that holds said peak
Implementation Method 3
a peak-divider configured to receive said detected-peak signal and to divide said detected-peak signal by a predetermined amount and thereby generate a divided-peak signal
Implementation Method 4
a comparator configured to receive said divided-peak signal and said filtered signal; said comparator configured to generate and output a pulse when a comparison between said divided-peak signal and said filtered signal results in a determination that said filtered signal exceeds said divided-peak signal
Implementation Method 5
said sensor configured to detect periodic movement and generate said electrical signal based on said periodic movement
Data Source
AI summary
The present specification provides a method, apparatus and system for sensing a signal with automatic adjustments for changing signal levels. A novel fractional peak discriminator circuit is provided which can be incorporated into a system for measuring periodic signals from moving elements. The circuit can be used regardless of whether the periodic signals are detected using optics, magnetic detector or other methods.