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quantization

Quantization is part of the digitization of analog signals. For this purpose, the analog signals are sampled at regular intervals at the sampling rate (sampling) and at each of these sampling times their voltage value is converted into a digital value. The analog signal can only be expressed in a finite number of digital values.

This conversion into numbers and measurable quantities is called quantization. For example, an analog value can be represented with a sampling depth of 4 bits, 8 bits, 16 bits, 24 bits or 32 bits, which corresponds to a quantization of 16, 256, 65,536, 16,777,216 or '4.295 *10^9' different levels. The higher the quantization, the greater the dynamic range and the lower the possible percentage quantization error with respect to the original signal.

A/D conversion with a sample depth of 4 bits

A/D conversion with a sample depth of 4 bits

Quantization methods work with linear and nonlinear conversion. With linear quantization, the quantization interval is constant and thus independent of the signal level. This leads to the disadvantage that the signal-to- noise ratio( SNR) is worse for small signal levels than for large ones.

The situation is different with nonlinear quantization. In these methods, the input signal is predistorted, small levels are raised, large levels are lowered. Non-linear quantizations work with non-linear characteristics, which have logarithmic functions or are designed as segment characteristics. The 13-segment characteristic is well known, which consists of 13 linear segments. In nonlinear quantization, the input signals are first compressed, then quantized, then transmitted and expanded again. This process significantly improves the signal-to-noise ratio and the dynamic range.

Informations:
Englisch: quantization
Updated at: 22.01.2022
#Words: 247
Links: analog, sampling rate, voltage, digital, signal
Translations: DE
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