Monday, April 1, 2002		Bits & Bytes

PSK: Short for phase-shift keying, a modulation technique used by modems in which different phase angles in the carrier signal are used to represent the binary states of 0 and 1. The simplest method of PSK, also called biphase modulation, uses two signal phases - 0 degrees and 180 degrees. The digital signal is broken up according to time into binary digits and the state (1 or 0) of each bit is determined according the state of the bit that preceded it. There are more complex forms of PSK that rely on four or eight phases to transmit data at a faster rate.

FSK: Short for frequency-shift keying, a modulation technique used by modems in which two different frequencies in the carrier signal are used to represent the binary states of 0 and 1. Using FSK, a modem converts the binary data from a computer into a binary form in which logic 1 is represented by an analog waveform at a specific frequency and logic 0 is represented by a wave at a different specific frequency.