Phase-Locked Loop Angle Measurement Circuit
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Solution Overview
Problem
Existing devices for measuring the angle of a magnetic field relative to a reference axis are cumbersome, with high circuit complexity, high power consumption, and latency, limiting their bandwidth and measurement accuracy.
Innovation Solution
A device utilizing a PLL phase-locked loop with a tracking oscillator and frequency mixer to synchronize digital oscillating signals with rotation scanning signals from magnetic field sensors, allowing for phase-synchronous detection of the magnetic field angle, and incorporating a multiplexer and comparator for noise shaping and improved signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple magnetic field sensors are read out cyclically in a rotating manner, then the angle measurement can be performed, but the reading process becomes time-consuming and the bandwidth is limited
Solution Approach 1:
The patent uses periodic action by implementing a phase-locked loop that synchronizes a digital oscillating signal with the periodic rotation scanning signal from the magnetic field sensors. The tracking oscillator generates digital oscillating signals at the same frequency as the rotation scanning, allowing phase comparison to determine the magnetic field angle. This periodic synchronization approach enables continuous angle measurement without the time-consuming sequential reading of multiple sensors, thereby increasing bandwidth while maintaining measurement precision.
2Reliability
If a non-feedback analog low-pass filter is used to smooth the measurement signal, then the signal can be processed, but the filter requires high linearity and frequency response which increases area requirement and power consumption
Solution Approach 1:
The patent replaces the analog low-pass filter with a digital signal processing approach using a phase-locked loop. Instead of using an analog filter to smooth the measurement signal, the system uses digital oscillating signals from the tracking oscillator and phase detection to extract the angle information. This substitution of analog filtering with digital phase-locked loop processing reduces the area requirement and power consumption while maintaining or improving signal processing quality and reliability.
3Extent of automation
If digital-to-analog conversion and decimation filtering are performed for each magnetic field sensor, then digital processing can be achieved, but the circuit complexity increases and latency is introduced
Solution Approach 1:
The patent merges the processing paths of multiple magnetic field sensors by using a single phase-locked loop to process the combined rotation scanning signal from all sensors. Instead of performing separate digital-to-analog conversion and decimation filtering for each sensor, the system combines the sensor outputs into a rotation scanning signal and processes this single signal through the PLL. This merging approach reduces circuit complexity while maintaining digital processing capability, and eliminates the latency introduced by multiple separate processing chains.
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 simplifies the device structure, reduces power consumption, increases measurement accuracy, and enables faster angle determination with reduced latency and noise, while adapting to application-specific frequency responses.
Implementation Method 1
the device has a PLL phase-locked loop with a tracking oscillator arranged in a phase-locked loop, that the tracking oscillator has at least one oscillator output for a digital oscillating signal
Implementation Method 2
at least two magnetic field sensors which are arranged with their measuring axes in and/or parallel to the plane and oriented transversely to one another
Data Source
Figure 1
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AI summary
The angle measuring device (1) has magnetic field sensors (3,4), and a phase-locked loop (5) with a lagging oscillator (6) arranged in a phase loop. The lagging oscillator has an oscillator output for a digital oscillating signal. The magnetic field sensors are coupled with the phase loop such that the digital oscillation signal is in phase synchronic to a rotation sample signal of the magnetic field sensors. An independent claim is included for a method for measuring an angle.