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Quantization Efficiency


Quantization is a nonlinear process which generates additional frequency components (Thompson et al. 1986). This means that the signal is no longer band-limited, so the sampling theorem no longer holds. If a signal is sampled at the Nyquist frequency, information will be lost. Therefore, sampling faster than the Nyquist frequency results in detection of more of the signal and a lower signal-to-noise ratio [SNR]. Let beta be the oversampling ratio and define

 eta_Q=(SNR_(quant))/(SNR_(unquant)).

Then the following table gives values of eta_Q for a number of parameters.

quantization levelseta_Q(beta=1)eta_Q(beta=2)
20.640.74
30.810.89
40.880.94

The Very Large Array of 27 radio telescopes in Socorro, New Mexico uses three-level quantization at beta=1, so eta_Q=0.81.


See also

Oversampling

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References

Thompson, A. R.; Moran, J. M.; and Swenson, G. W. Jr. Fig. 8.3 in Interferometry and Synthesis in Radio Astronomy. New York: Wiley, p. 220, 1986.

Referenced on Wolfram|Alpha

Quantization Efficiency

Cite this as:

Weisstein, Eric W. "Quantization Efficiency." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/QuantizationEfficiency.html

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