Vaihevasteiden

Vaihevasteiden, often translated as phase-shift keying (PSK), is a digital modulation scheme that transmits data by changing the phase of a carrier wave. In PSK, information is encoded by altering the phase of the reference signal. The number of possible phase shifts determines the number of bits that can be transmitted per symbol. For example, binary phase-shift keying (BPSK) uses two phases, typically 0 and 180 degrees, to represent a single bit (0 or 1).

Quadrature phase-shift keying (QPSK) is a more advanced form that uses four phase shifts, usually separated by 90 degrees, to transmit two bits per symbol. This allows for a higher data rate compared to BPSK. Higher-order PSK schemes, such as 8-PSK and 16-PSK, utilize even more phase states, enabling further increases in data throughput but at the cost of requiring a cleaner signal and more complex receivers.

The key advantage of PSK is its robustness against noise and interference, especially when compared to amplitude-shift keying (ASK). The receiver primarily relies on detecting phase differences, which are less susceptible to amplitude variations. PSK is widely used in various communication systems, including Wi-Fi, satellite communications, and cellular networks, for its efficiency and reliability in transmitting digital data. The implementation of PSK involves generating a carrier wave and then shifting its phase according to the digital data stream to be transmitted.