ASIC with Interpolator for Incremental Optical Encoders

Optical encoders are commonly used in modern positioning systems. The accuracy and resolution of the optical encoder is always restricted by generated sinusoidal signals and the assembly technique. The interpolation circuit and conditional circuit in the optical sensor are preferably integrated into the integrated circuit (IC) to maximize the signal-to-noise-ratio (SNR). Nowadays, system-on-a-chip (SOC) is popular device to minimize the circuit and the cost to the manufacturer of making it. This study presents an ASIC including a conditional circuit for optical signal and a 10-fold interpolation circuit for improving the resolution of optical encoder. Furthermore, an electrical method of reducing the assembly difficulties is proposed. The ASIC is fabricated in a 0.5μm 2P2M CMOS process.

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