PAM4tekniikka

PAM4tekniikka, also known as Pulse Amplitude Modulation with four levels, is a digital modulation scheme used in telecommunications. It encodes data by varying the amplitude of a carrier signal across four distinct levels. Each level represents two bits of data, effectively doubling the data rate compared to traditional non-return-to-zero (NRZ) signaling which uses two levels for one bit.

The core principle of PAM4 involves sending signals at different voltage levels. For instance, a signal could have voltage levels representing 00, 01, 10, and 11 binary combinations. This increased spectral efficiency is crucial for high-speed data transmission, particularly in applications like Ethernet and optical networking where bandwidth is a limiting factor.

However, PAM4 also presents challenges. The closer proximity of the four amplitude levels makes the signal more susceptible to noise and intersymbol interference (ISI). This requires more sophisticated signal processing techniques, such as advanced equalization and error correction coding, to accurately decode the transmitted data. Despite these complexities, PAM4 has become a cornerstone technology for achieving higher data rates in modern communication systems.