Faseskiftkoding

Faseskiftkoding, or phase shift keying (PSK), is a digital modulation scheme that conveys data by changing the phase of a reference signal. In essence, information is encoded in the phase shifts of a carrier wave. Different phase states represent different binary values. For example, a simple form like Binary Phase Shift Keying (BPSK) uses two phase states, typically 0 and 180 degrees, to represent a 0 or a 1. More complex variations, such as Quadrature Phase Shift Keying (QPSK), employ four phase states, allowing for the transmission of two bits per symbol.

The process of faseskiftkoding involves a modulator at the transmitter and a demodulator at the receiver. The modulator shifts the phase of the carrier signal according to the incoming digital data stream. The demodulator then detects these phase shifts to reconstruct the original data. The advantage of PSK lies in its robustness against noise and interference, especially compared to amplitude modulation techniques. However, it requires more complex circuitry for synchronization and phase detection. PSK is widely used in various communication systems, including Wi-Fi, satellite communications, and mobile telephony, due to its efficiency in bandwidth utilization and reliable data transmission.