Okta Okta In meteorology, an okta is a unit of measurement used to describe the amount of cloud cover at any given location such as a weather station. Sky conditions are estimated in terms of how many eighths of the sky are covered in cloud, ranging from 0 oktas (completely clear sky) through to 8 oktas (completely overcast). In addition, in the SYNOP code there is an extra cloud cover indicator '9' indicating that the sky is totally obscured (i.e. hidden from view), usually due to dense fog or heavy snow. When used in weather charts, okta measurements are shown by
Phasor measurement unit it, or, if this is not done, as Rob Landley put it, "people's light bulbs start exploding." This measurement function is what these devices do. A PMU can measure 50/60 Hz AC waveforms (voltages and currents) typically at a rate of 48 samples per cycle. The analog AC waveforms are digitized by an analog-to-digital converter for each phase. A phase-locked oscillator along with a Global Positioning System (GPS) reference source provides the needed high-speed synchronized sampling with 1 microsecond accuracy. However, PMUs can take in multiple time sources including non-GPS references as long as they are all calibrated and working