| 单词 | PSK (Phase-Shift Keying) |
| 释义 | PSK (Phase-Shift Keying) Also known as PM (Phase Modulation). A signal modulation technique that involves the carefully synchronized shifting of the phase (i.e., position) of the sine wave in order to represent digital bits across an analog carrier.The transmitting computer outputs a baseband electrical signal, defining 1 bits and 0 bits as discrete voltage levels. Binary phase-shift keying (BPSK) is a unibit technique in which a continuous sine wave pattern is interrupted and restarted at the baseline with a 180° phase shift to indicate a change in value from a 1 bit to a 0 bit or from a 0 bit to a 1 bit. See Figure P-7. Differential phase-shift keying (DPSK) is a unibit PSK scheme in which each 1 bit triggers a 180° phase shift, but 0 bits have no effect. Quadrature phase-shift keying (QPSK), also known as quaternary phase-shift keying and quadriphase keying, is a dibit technique achieved by defining four phase shifts separated by 90 degrees (0°, 90°, 180°, and 270°) and thereby impressing two bits on every phase shift. PSK can be used in conjunction with amplitude modulation (AM) and frequency modulation (FM). See also AM, analog, baseband, bit, carrier, FM, modulation, phase, signal, sine wave, and synchronize. 0 1 0 0 1 1 1 0 Baseband Digital Signal Modulated Carrier |
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