Scicos Block
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Gaussian White Noise Generator block

Contents

• Gaussian White Noise Generator block
  • Palette
  • Description
  • Dialog box
  • Default properties
  • Interfacing function
  • Computational function
  • See also
  • Authors

Palette

• Sources - Sources palette

Description

In communication system simulator, a Gaussian noise generator is generally computed using the box Muller law. This method allows noising both amplitude and phase a given complex value. It is defined with these two equations:

$$\begin{eqnarray} \tilde{I}&=&\sigma\sqrt{-\log(\tilde{p})\:\cos(2\pi\tilde{q})}\\ \tilde{Q}&=&\sigma\sqrt{-\log(\tilde{p})\:\sin(2\pi\tilde{q})} \end{eqnarray}$$

where $\tilde{p}$ and $\tilde{q}$ are two uniform random variables, $\sigma$ the variance of the noise source and $\tilde{I}$ $\tilde{Q}$ the real and imaginary part of the noisy complex sample.

Dialog box

• Size of outputs
  The size of the regular output port
  Properties : Type 'vec' of size 1. Integer.

• sigma
  The variance of the noise generator.
  Properties : Type 'vec' of size -1. Vector of real

• mean
  The mean of the noise generator.
  Properties : Type 'vec' of size -1. Vector of real.

• seed
  The seed of the noise generator.
  Properties : Type 'vec' of size 1. Scalar.

• Type
  The type of the noise generator.
  Properties : Type 'vec' of size 1. Integer.
  • 0 for a cosine output

  • 1 for a sine output

  • 2 for both cosine and sine output (two regular outputs)

Default properties

• always active: no
• direct-feedthrough: no
• zero-crossing: no
• mode: no
• regular outputs:
  - port 1 : size [64,1] / type 1
  
• number/sizes of activation inputs: 1
• number/sizes of activation outputs: 0
• continuous-time state: no
• discrete-time state: no
• object discrete-time state: no
• name of computational function: noiseblk

Interfacing function

• MODNUMCOS/macros/scicos_blocks/Sources/NOISEBLK_f.sci [view code]

Computational function

• MODNUMCOS/routines/sources/noiseblk.c (Type 4) [view code]

See also

• noiseblk_c - white gaussian noise generator computational routine (Low level routine)

Authors

A. Layec