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Phase-Shift Keying

What Does Phase-Shift Keying Mean?

Phase-shift keying (PSK) is a digital modulation scheme based on changing, or modulating, the initial phase of a carrier signal. PSK is used to represent digital information, such as binary digits zero (0) and one (1).


PSK is typically applied in wireless local area networks (WLAN), Bluetooth technology and radio frequency identification (RFID) standards used in biometric passport and contactless payment systems.

Techopedia Explains Phase-Shift Keying

The three primary digital modulation types – PSK, frequency-shift keying (FSK) and amplitude-shift keying (ASK) – modify base signals for data communication. PSK conveys data by modifying the phase of a signal.

Two common PSK types are as follows:

  • Quadrature Phase-Shift Keying (QPSK): Uses four phases to encode two bits per symbol.
  • Binary Phase-Shift Keying (BPSK): Simplest PSK type. Uses two phases separated by 180 degrees.

More complex PSK schemes may use more than four phases for data transmission. However, eight is the maximum.


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