NyquistAnforderung

NyquistAnforderung, often translated as the Nyquist requirement or Nyquist criterion, is a fundamental principle in digital signal processing. It states that to accurately reconstruct a continuous-time signal from its discrete samples, the sampling frequency must be at least twice the highest frequency component present in the signal. This minimum sampling rate is known as the Nyquist rate, and the condition itself is the Nyquist-Shannon sampling theorem.

If the sampling frequency is below this threshold, a phenomenon called aliasing occurs. Aliasing is when higher frequencies in the original signal are incorrectly represented as lower frequencies in the sampled data. This distortion makes it impossible to recover the original signal without errors, even with perfect reconstruction techniques.

The NyquistAnforderung is crucial for preventing aliasing. To ensure that all relevant frequency information is captured, anti-aliasing filters are typically used before sampling. These filters remove or attenuate frequencies above half the sampling rate, thus satisfying the Nyquist criterion. Understanding and applying the NyquistAnforderung is essential in fields such as telecommunications, audio recording, image processing, and any application involving the conversion of analog signals to digital representations. It forms the bedrock of digital signal acquisition and processing.