Local Oscillator Phase Correction for Accurate Distance Measurement
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Solution Overview
Problem
Existing distance measuring devices using a digital-controlled oscillator (DCO) direct modulation method for transmission and a super-heterodyne (SH) method for reception suffer from initial phase fluctuations in the local oscillator, leading to inaccurate distance measurements due to the difficulty in canceling out initial phase changes during frequency setting changes.
Innovation Solution
A phase correcting device with an all-digital phase-locked loop, a reference phase device, and a correction circuit is employed to detect and correct phase fluctuations, allowing for accurate distance measurement by generating a quasi-reference phase and calculating phase differences to compensate for initial phase changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a DCO direct modulation method is used for transmission and an SH method is used for reception to reduce power consumption, then power consumption is reduced, but initial phase fluctuates in the local oscillator leading to measurement inaccuracy
Solution Approach 1:
The patent applies preliminary action by detecting the initial phase of the local oscillator before frequency setting changes occur, storing this phase information, and then using it for correction after the frequency change. This allows the system to compensate for phase fluctuations that inevitably occur when using low-power DCO direct modulation and SH methods, thereby maintaining measurement accuracy while achieving reduced power consumption.
2Adaptability or versatility
If frequency setting is changed in the local oscillator to enable distance measurement, then distance measurement becomes possible, but initial phase changes occur leading to measurement errors
Solution Approach 1:
The patent implements feedback by continuously monitoring the initial phase of the local oscillator, comparing it with the phase after frequency setting changes, detecting the phase difference, and using this feedback information to correct subsequent phase measurements. This feedback mechanism enables the system to maintain high measurement precision despite frequent frequency setting changes required for adaptable distance measurement.
3Measurement precision
If phase information is transmitted between devices to calculate distance, then distance measurement accuracy is improved, but the system becomes more complex
Solution Approach 1:
The patent uses the detected initial phase information as an intermediary element that mediates between the frequency setting changes and the phase measurement process. By introducing this intermediate phase correction parameter, the system can achieve high distance measurement accuracy without requiring complex inter-device communication protocols, thus reducing overall system complexity while maintaining precision.
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 accurate distance measurement by stabilizing the initial phase, thereby improving the precision of distance calculations in distance measuring systems, even when using DCO direct modulation and SH methods.
Implementation Method 1
a first phase detector included in the all digital phase-locked loop, and configured to detect a phase of the local oscillation signal
Implementation Method 2
a correction circuit configured to correct the phase of the inputted signal by using a detection result of the second phase detector
Data Source
AI summary
A phase correcting device includes a local oscillator that includes an all digital phase-locked loop configured to output a local oscillation signal, a first phase detector configured to detect a phase of the local oscillation signal to output the phase of the local oscillation signal, a reference phase device configured to generate a quasi-reference phase corresponding to a reference phase of the local oscillation signal to output the quasi-reference phase, based on a reference clock, a second phase detector configured to detect a fluctuation amount of a phase of the local oscillator, based on the phase detected by the first phase detector and the quasi-reference phase, and a correction circuit configured to correct the phase of the inputted signal by using a detection result of the second phase detector.