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

Abstract

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.

High-Resolution Permanent Magnet Drive Using Separated Observers for Acceleration Estimation and Control

“…The position measurement resolution is improved by compensating both signal offset and magnitude deviation. In [ 5 , 6 ], the resolution of the same analog encoder is enhanced by the digital phase-locked loop with the phase and frequency transformation. However, these improvement methods are based on the signal condition correction.…”

Research on Subdivision System of Sin-Cos Encoder Based on Zero Phase Bandpass Filter

“…In precision measurement and control systems with high dynamic and precision performance requirements, the position and rotational speed of the rotator must be accurately measured and perceived. The high-precision Sin-Cos Encoder (SCE) is a kind of sensor that converts the geometric displacement of the rotating shaft into a digital quantity [1]. Based on the digital quantity, the rotator position and speed detection are realized by alternative technologies.…”

A Fine-Grained, Uniform, Energy-Efficient Delay Element for FD-SOI Technologies

“…The delay granularity provided by programmable DEs is an important concern. For instance, systems that require precise timing control, such as phase shift compensators [8], timing generators [9] and timing verniers [10], used for delay fault testing in automatic testing equipment, employ finegrained DEs to ensure correct operation. In essence, the precision to which these DEs can be tuned affects the amount of timing margin they can effectively avoid.…”