Linear Optical Encoder System With Sinusoidal Signal Distortion Below $-$60 dB

Rozman, Jernej; Pleteršek, Anton

doi:10.1109/tim.2009.2027774

Cited by 28 publications

(14 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to achieve a precise delay, the integrated circuit is designed in such a way that the delay only depends on the ratio of the resistors. 9 If the signals are perfect and the frequency is low, then the precision of the delay is only limited by the systematic error ϕ err − s and the resistors' ratio. The detailed worst case analysis and simulation shows that for the eventually integrated version with the 128-tap DP ( R/R = 1 LSB = 0.8 %), the resistors' tolerances contribute 0.34°to the total error and typical irregularities of the signal of about 0.40°.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Precision Delay Circuit for Analog Quadrature Signals in Sin/Cos Encoders

Dogša

Solar

Jarc

2014

IEEE Trans. Instrum. Meas.

View full text Add to dashboard Cite

This paper considers the problem of setting small and accurate delay of those analog quadrature signals generated in the sin/cos encoders within the range of ±10°. Such precision is needed for the efficient phase shift compensation. A typical analog delay circuit is comprised of a summing amplifier and digitally controlled variable resistor used to set a delay of the cos signal. The main disadvantage of this delay circuit is poor linearity. We propose a new circuit based on a voltage divider with about three times better linearity and a completely symmetrical range. The effects of the component tolerances and signals' irregularities on the accuracy of the delay are explored. The detailed theoretical worst case analysis and simulation shows that for the integrated version with the 128-tap digital potentiometer ( R/R = 1 LSB = 0.8%), the tolerances contribute 0.34°to the total error and typical signal irregularities of ∼0.40°. The measurement of the prototype circuit shows that with the discrete elements it is possible to obtain a total error of below 0.2°within the range from 0°to 5°, if the signals are of good quality.Index Terms-Analog quadrature signals, delay circuit, error analysis, phase delay, quadrature encoder signals.

show abstract

Section: Discussionmentioning

confidence: 99%

“…These approaches generally require high-precision ADCs and high-speed DSP to compute the angle to the required resolution. A harmonic distortion reduction achieved by the adequate design of a reading plate is also reported in [9]. All the proposed methods have been aimed toward compensating for the imperfections.…”

Section: Introductionmentioning

confidence: 99%

Precision Delay Circuit for Analog Quadrature Signals in Sin/Cos Encoders

Dogša

Solar

Jarc

2014

IEEE Trans. Instrum. Meas.

View full text Add to dashboard Cite

show abstract

“…The quality of the electrical signals highly depends on various aspects, like the optical-scanning principle, the design of a reading head and its ability to handle various deformations [32], mechanical vibrations [33][34][35], or temperature variations [36,37]. In order to improve signal quality and to make encoders more robust, manufacturers use advanced optical-scanning methods such as the single-field or interferential scanning principle [38,39], or they implement special-configuration multiple-track analyzer grating to eliminate higher-order harmonic signals [40]. Unfortunately, all such improvements require more complex encoder configurations and expensive optical parts.…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of Linear Encoder’s Subdivisional Errors under Different Scanning Speeds

2020

View full text Add to dashboard Cite

Optical encoders are widely used in applications requiring precise displacement measurement and fluent motion control. To reach high positioning accuracy and repeatability, and to create a more stable speed-control loop, essential attention must be directed to the subdivisional error (SDE) of the used encoder. This error influences the interpolation process and restricts the ability to achieve a high resolution. The SDE could be caused by various factors, such as the particular design of the reading head and the optical scanning principle, quality of the measuring scale, any kind of relative orientation changes between the optical components caused by mechanical vibrations or deformations, or scanning speed. If the distorted analog signals are not corrected before interpolation, it is very important to know the limitations of the used encoder. The methodology described in this paper could be used to determine the magnitude of an SDE and its trend. This method is based on a constant-speed test and does not require high-accuracy reference. The performed experimental investigation of the standard optical linear encoder SDE under different scanning speeds revealed the linear relationship between the tested encoder’s traversing velocity and the error value. A more detailed investigation of the obtained results was done on the basis of fast Fourier transformation (FFT) to understand the physical nature of the SDE, and to consider how to improve the performance of the encoder.

show abstract

“…Furthermore, digital signal processing circuitry can also be added to integrated sensor systems, thus creating a cost-efficient mixed signal sensor system [ 3 ]. Optical position encoders can also be integrated in a similar manner [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

A Differential Monolithically Integrated Inductive Linear Displacement Measurement Microsystem

Podhraški

Trontelj

2016

Sensors

View full text Add to dashboard Cite

An inductive linear displacement measurement microsystem realized as a monolithic Application-Specific Integrated Circuit (ASIC) is presented. The system comprises integrated microtransformers as sensing elements, and analog front-end electronics for signal processing and demodulation, both jointly fabricated in a conventional commercially available four-metal 350-nm CMOS process. The key novelty of the presented system is its full integration, straightforward fabrication, and ease of application, requiring no external light or magnetic field source. Such systems therefore have the possibility of substituting certain conventional position encoder types. The microtransformers are excited by an AC signal in MHz range. The displacement information is modulated into the AC signal by a metal grating scale placed over the microsystem, employing a differential measurement principle. Homodyne mixing is used for the demodulation of the scale displacement information, returned by the ASIC as a DC signal in two quadrature channels allowing the determination of linear position of the target scale. The microsystem design, simulations, and characterization are presented. Various system operating conditions such as frequency, phase, target scale material and distance have been experimentally evaluated. The best results have been achieved at 4 MHz, demonstrating a linear resolution of 20 µm with steel and copper scale, having respective sensitivities of 0.71 V/mm and 0.99 V/mm.

show abstract

Linear Optical Encoder System With Sinusoidal Signal Distortion Below $-$60 dB

Cited by 28 publications

References 21 publications

Precision Delay Circuit for Analog Quadrature Signals in Sin/Cos Encoders

Precision Delay Circuit for Analog Quadrature Signals in Sin/Cos Encoders

Experimental Investigation of Linear Encoder’s Subdivisional Errors under Different Scanning Speeds

A Differential Monolithically Integrated Inductive Linear Displacement Measurement Microsystem

Contact Info

Product

Resources

About