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Altera_Forum
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15 years ago

How to determine if 2 signals are in quadrature

Hello friends, I need to determine if two signals are precisely on 90 deg. phase. In fact, there is a xor phase comparator and I try to catch lock condition as indicator (for viewing purposes, ...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

The signals are logic and located inside CPLD along with xor for detection.

All right then, 0.1deg error. I guess oversampling with greater clock then compare against previous period. Initially a LED indicating "lock" within error would be sufficient but then I further want to transmit actual phase error to some MCU (SPI, bus, I don't know yet and/or space in CPLD).