How can incremental linear encoder signal subdivision technology improve measurement resolution?
Release Time : 2026-02-26
As a core component in precision measurement, the incremental linear encoder's signal subdivision technology significantly improves the system's measurement resolution by optimizing the processing of the original pulse signal. This process relies not only on improvements in hardware design but also on innovations in signal processing algorithms. Its core objective is to extract more effective information from a limited number of physical etched lines, thereby meeting the demands of high-precision industrial applications.
From a hardware perspective, the subdivision technology of the incremental linear encoder primarily depends on improved precision in code disk manufacturing. As the source of signal generation, the density of the etched lines on the code disk directly determines the richness of the original signal. By employing ultra-precision manufacturing processes, such as nanoscale photolithography, finer etched lines can be formed on the code disk surface, significantly increasing the number of etched lines per unit length. This physical optimization provides higher-density raw data for subsequent signal processing, laying the foundation for subdivision technology. Simultaneously, the selection of high-precision optical components is also crucial. The combination of a high-resolution photodetector and a high-quality optical lens can accurately capture subtle changes in light intensity at the edges of the etched lines, reducing signal loss and distortion, and ensuring the integrity of the original signal.
In the signal processing stage, the core of subdivision technology lies in the interpolation and reconstruction of the original pulse signal. Traditional incremental encoders count pulses by detecting only the rising or falling edge, while subdivision techniques further extract timing information from the pulse signal. For example, frequency quadrupling technology subdivides each original pulse into four equivalent pulses by simultaneously detecting both the rising and falling edges, thus increasing the resolution to four times the original without changing the hardware scribe line density. More advanced subdivision algorithms, such as phase difference analysis based on orthogonal signals, can further infer the sub-gradient displacement between scribe lines by calculating the phase relationship between phases A and B, achieving even higher subdivision ratios.
Moiré fringe subdivision technology is another important resolution enhancement method in incremental linear encoders. When the encoder's grating and indicator grating move relative to each other, alternating bright and dark moiré fringes are formed. The spacing between these fringes is much larger than the width of a single scribe line. The displacement changes of the fringes can be converted into sinusoidal electrical signals by a photoelectric receiving circuit. Using electronic subdivision methods, such as interpolation algorithms or phase-locked loop (PLL) technology, these sinusoidal signals can be subdivided at high ratios, thereby obtaining a resolution superior to that of a single scribe line spacing. This technology not only improves measurement accuracy but also enhances the system's anti-interference capability, making it suitable for high-speed, high-precision dynamic measurement scenarios.
Noise suppression and filtering techniques also play a crucial role in the subdivision process. The original signal inevitably contains noise components such as electromagnetic interference and mechanical vibration, which can mask weak displacement signals and reduce subdivision accuracy. Hardware measures such as shielded cables and differential signal transmission can effectively reduce the introduction of external interference. Simultaneously, at the software level, digital filtering algorithms such as Kalman filtering and low-pass filtering can process the acquired signal in real time, filtering out high-frequency noise and extracting true and effective displacement information, thereby ensuring the accuracy of the subdivision results.
The implementation of subdivision technology also needs to consider the dynamic response characteristics of the system. In high-speed or high-frequency vibration environments, transient changes in the signal may exceed the processing capacity of the subdivision algorithm, leading to decreased resolution or measurement errors. Therefore, the design of the subdivision algorithm must balance accuracy and speed, ensuring stable subdivision performance even under high-speed motion by optimizing the algorithm structure or employing hardware acceleration.
The final effect of the subdivision technology still needs further optimization through calibration and compensation. Due to manufacturing errors, installation deviations, and other factors, the actual output signal of an encoder may deviate from the theoretical value. By establishing an accurate error model and making corresponding compensation adjustments to the subdivision algorithm, these systematic errors can be effectively eliminated, improving the absolute accuracy of the measurement.