What does QPSK stand for?

QPSK stands for Quadrature Phase Shift Keying. This modulation scheme is widely used in digital communications due to its efficiency in transmitting data. The term "quadrature" refers to the technique of using two different phase shifts to encode data, effectively allowing for the simultaneous transmission of multiple bits. In QPSK, each symbol represents two bits of information, which effectively doubles the data rate compared to simpler modulation schemes like Binary Phase Shift Keying (BPSK), where each symbol only represents one bit.

The concept of "phase shift" is essential because it refers to the changes made in the phase of the carrier signal to convey information. By shifting the phase of the signal in a controlled manner, QPSK is able to minimize error rates and improve signal robustness during transmission.

This understanding of QPSK's working principles clarifies its application in modern communication systems, such as satellite broadcasting, wireless networks, and broadband technologies, where efficient data transmission is paramount. Other options, while they use similar terminology, either mischaracterize the modulation technique or introduce terms that are not recognized in this context.