Krydstætning

Krydstætning refers to a phenomenon in digital signal processing and telecommunications where a transmitted signal interferes with itself due to multipath propagation. This occurs when the signal arrives at the receiver via multiple paths, each with a different delay and attenuation. When these delayed copies of the signal overlap in time, they can distort the original signal, leading to errors in demodulation.

The term "krydstætning" translates roughly to "cross-sclerosis" or "cross-clutter" in English, highlighting the idea of the signal becoming "cluttered" or obscured by its own delayed versions. This effect is particularly problematic in systems that use simple modulation schemes or have a narrow bandwidth, as the overlapping delayed signals can be difficult to distinguish from the primary signal.

Techniques to mitigate krydstætning include equalization, which attempts to compensate for the distortion introduced by multipath. Adaptive equalizers are often employed, as they can adjust their parameters dynamically to counteract changing channel conditions. Spread spectrum techniques and sophisticated coding schemes can also help to combat the effects of krydstætning by making the signal more robust to interference. Understanding and managing krydstætning is crucial for achieving reliable communication in environments prone to multipath effects, such as urban areas or indoor settings.