Filter Design Toolbox

range

Return the numerical range of quantizers in a quantized FFT, or the range of a quantizer

Syntax

• range(F)
  rtwiddle = range(F)
  [rtwiddle, rinput, routput, rproduct, rsum] = range(F)
  [r1, r2, ...] = range(F, formattype1, formattype2, ...)
  r = range(q)
  [a, b] = range(q)
  

Description

range(F) displays the numerical range of all the quantizers in quantized FFT F.

rtwiddle = range(F) returns the numerical range of the twiddle factor quantizer (although twiddle factors always have magnitudes less than 1).

[rtwiddle, rinput, routput, rproduct, rsum] = range(F) returns the range of each of the quantizers.

[r1, r2,...] = range(F, formattype1, formattype2,...) returns the range of the quantizers specified by strings formattype i, which may take on the values 'twiddle', 'input', 'output', 'product', 'sum'.

r = range(q) returns the two-element row vector r = [a b] such that for all real x, y = quantize(q,x) returns y in the range a y b.

[a, b] = range(q) returns the minimum and maximum values of the range in separate output variables.

Examples

• q = quantizer('float',[6 3]); 
  r = range(q) 
  

returns r = [-14, 14].

• q = quantizer('fixed',[4 2],'floor'); 
  [a,b] = range(q) 
  

returns a = -2, b = 1.75 = 2 -eps(q).

Algorithm

If q is a floating-point quantizer, a = -realmax(q), b = realmax(q).

If q is a signed fixed-point quantizer (mode = 'fixed'),

If q is an unsigned fixed-point quantizer (mode = 'ufixed'),

a = 0

See realmax for more information.

Errors

If you use more than two output arguments, MATLAB returns the error message Too many output arguments and aborts the function.

See Also
realmax, realmin, exponentmin, fractionlength

randquant

realizemdl