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SNDR (Signal-to-Noise-and-Distortion Ratio)

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SNDR, which stands for Signal-to-Noise-and-Distortion Ratio, is a measurement used in electronics and signal processing to assess the quality of a signal. It quantifies the ratio of the desired signal power to the combined power of noise and distortion components in a signal.

To understand SNDR in detail, let's break down the components involved:

  1. Signal: The signal refers to the desired information or data that is being processed or transmitted. In an ideal scenario, the signal is free from any unwanted interference, noise, or distortion.
  2. Noise: Noise is an unwanted random signal that interferes with the desired signal. It can originate from various sources such as electrical components, thermal effects, electromagnetic radiation, or external sources. Noise introduces additional power to the signal, degrading its quality.
  3. Distortion: Distortion refers to any unwanted alteration or modification of the signal waveform. It can be caused by non-linearities in electronic components, imperfect transmission channels, or other factors. Distortion introduces additional power or changes the shape of the signal, resulting in signal degradation.

The SNDR is defined as the ratio of the power of the signal to the combined power of noise and distortion. It is typically expressed in decibels (dB). Mathematically, SNDR is calculated as follows:

SNDR (dB) = 10 * log10(P_signal / (P_noise + P_distortion))

where:

  • P_signal is the power of the signal.
  • P_noise is the power of the noise component.
  • P_distortion is the power of the distortion component.

A higher SNDR value indicates a better signal quality, as it signifies that the desired signal power is significantly larger than the combined power of noise and distortion. Conversely, a lower SNDR value indicates a poorer signal quality, with more interference affecting the signal.

SNDR is a fundamental metric used in many applications, including audio processing, image processing, telecommunications, and analog-to-digital converters (ADCs). It helps evaluate the performance of electronic systems by quantifying the amount of unwanted signal degradation in the presence of noise and distortion.