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Pulse position modulation
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Ppm, английский
- Относительная погрешность в миллионных долях:
- Parts per million (1/ppm = 0.000001). generally by weight. 100 ppm = 0.01%; 10,000 ppm = 1%
- Parts per million
- Pounds per minute
- Pulse phase
- Pulses per minute
- Portable pixelmap (format)
- Parts per million.
- Abbr. for parts per million. pr on drawings, abbr. for “pair.”
- Pages per minute
- Passenger protective message (phm)
- Policies and procedures manual (isago orm-hs 2.2.1 section) ppm is a generic name, an acceptable alternative name is gom
- Pulse position modulation
- Planned preventive maintenance
- Project portfolio management (управление портфелем проектов)
Фазоимпульсная модуляция, фим, русский
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Psk, английский
Кодирование со сдвигом фазы; фазовая манипуляция
Pulse modulation, английский
A method akin to digital modulation where the intensity of a carrier is modulated between two states, either maximum or zero. if the pulse width is small and the repetition rate slow, the peak power in the pulse can be vastly above that of the mean power. for instance, if a pulse of 1 nanosecond (10-9 sec) duration is transmitted every second, then the peak power is 1 billion times or 109 (90 db) above the mean power. it is very easy for this "lighthouse" laser beacon to outshine a star during each brief flash. during each flash, the rate at which photons arrive at the receiver is much higher than from the stellar or sky backgrounds. for the example given, this ratio can be as high as 10 million times.
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