Optical Encoder Phase Shifter Circuit for Signal Phase Alignment
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Solution Overview
Problem
Existing incremental optical encoders face issues with phase deviations between incremental signals and index signals due to spatial misalignments, leading to inaccurate position determination.
Innovation Solution
A phase shifter circuit utilizing resistor strings and amplifiers with adjustable feedback resistors to correct phase shifts between incremental signals and index signals, employing switching devices to align phases and compensate for signal attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spatial alignment of components is improved, then phase deviation between signals is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent introduces a phase shifter circuit as an intermediary component between the optical encoding system and the signal processing system. This circuit actively compensates for phase deviations caused by spatial misalignments, allowing the system to achieve high measurement precision without requiring extremely tight manufacturing tolerances for component alignment.
Solution Approach 2:
The phase shifter circuit dynamically adjusts signal phase parameters to compensate for spatial deviations. By changing the phase parameter of the index signal or incremental signals through electronic control, the system can correct alignment errors without physically repositioning components, thereby relaxing manufacturing precision requirements.
2Measurement precision
If phase calibration components are added, then signal alignment accuracy is improved, but device complexity increases
Solution Approach 1:
The phase shifter circuit is designed to perform multiple functions: it can adjust phase of different signals (index signal or incremental signals), work with different spatial deviation scenarios, and integrate into existing encoder architectures. This multi-functionality reduces the need for separate calibration mechanisms for different error types, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent replaces mechanical alignment adjustment mechanisms with electronic phase shifting. Instead of using movable mechanical components to physically align signals, the system uses electronic phase shifters to achieve alignment through signal processing, reducing mechanical complexity while improving phase alignment accuracy.
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 phase shifter circuit effectively aligns and amplifies signals to ensure precise position detection by correcting phase deviations, enhancing the accuracy of incremental optical encoders.
Implementation Method 1
The four feedback resistors are respectively coupled between one input and one output of the first amplifier and the second amplifier, wherein a ratio of one feedback resistor and the input resistor is determined corresponding to a conducting of the multiple switching devices
Data Source
AI summary
There is provided a phase shifter circuit of an optical encoder. The phase shifter circuit receives a first signal, a second signal, a third signal and a fourth signal sequentially having a 90-degree phase shift, and includes a first cascaded resistor string, a second cascaded resistor string, a third cascaded resistor string and a fourth cascaded resistor string. The first, second, third and fourth cascaded resistor strings respectively delay the first, third, second and fourth signals by selecting a switch connected at a tap-out node of the first, second, third and fourth cascaded resistor strings to correct phase deviations between incremental signals and an index signal and/or between incremental signals.