Fixed-Point Toolbox™

errvar - Variance of quantization error

Syntax

v = errvar(q)

Description

v = errvar(q) returns the variance of a uniformly distributed random quantization error that arises from quantizing a signal by quantizer object q.

Note   The results are not exact when the signal precision is close to the precision of the quantizer.

Examples

Find v, the variance of the quantization error for quantizer object q:

q = quantizer;
v = errvar(q)

v =

    7.761021455128987e-011

Now compare v to v_est, the sample variance from a Monte Carlo experiment:

r = realmax(q);
      u = 2*r*rand(1000,1)-r;  % Original signal
      y = quantize(q,u);     % Quantized signal
      e = y - u;           % Error
      v_est = var(e)     % Estimate of the error variance

v_est =

    7.520208858166330e-011

See Also

errmean, errpdf, quantize

errpdf

etreeplot