QPSK (Quadrature Phase Shift Keying) modulation is a type of phase modulation where data is transmitted by varying the phase of a carrier signal. In QPSK, four different phase shifts (0°, 90°, 180°, and 270°) represent four different data symbols. This modulation scheme allows for the transmission of two bits of data per symbol, increasing data throughput compared to simpler modulation schemes.
What is modulation? Briefly defined.
Modulation is a technique used to encode information onto a carrier signal by varying its properties, such as amplitude, frequency, or phase. This process allows the information to be transmitted over communication channels effectively. Modulation helps in adapting the signal for transmission over long distances and overcoming channel impairments.
BPSK (Binary Phase Shift Keying) modulation is a type of phase modulation where data is transmitted by changing the phase of the carrier signal between two states, typically 0° and 180°. Each phase shift represents a binary digit (0 or 1). BPSK is known for its simplicity and robustness against noise but has a lower data rate compared to more advanced modulation schemes.
The modulation feature refers to the specific method or technique used to encode data onto a carrier signal. It includes various modulation schemes like amplitude modulation (AM), frequency modulation (FM), phase modulation (PM), and their variants. The choice of modulation feature impacts the efficiency, data rate, and robustness of the communication system.
GMSK (Gaussian Minimum Shift Keying) modulation is a type of continuous-phase modulation where data is transmitted by varying the frequency of the carrier signal. The Gaussian filter is used to smooth the frequency transitions, reducing the bandwidth and minimizing signal distortion. GMSK is often used in GSM (Global System for Mobile Communications) due to its spectral efficiency and improved performance in mobile communication environments.
