SPPE-1000 White Paper
This white paper discusses a new position encoder product (SPPE-1000), which integrates SPPE (scanning probe position encoder) technology developed by NanoWave Inc. and modulated laser interference encoder optics developed by Nikon Corporation. High frequency scan of laser beam on a moving scale creates harmonic signals which contain position information. Low-latency phase detection logic using PLL (Phase-Locked Loop) decodes the position information down to 7.6pm LSB from 4 micrometer pitch grating scale, all with spectrum noise density better than. The entire signal processing logic is compact enough to be implemented within a single low-cost FPGA chip, which also keeps the cost of the system low. Its relatively long grating pitch simplifies the installation process significantly and results in great robustness in attaining the specified accuracy.
