Scicos Block
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Spectrum analyzer scope block

Contents

• Spectrum analyzer scope block
  • Palette
  • Dialog box
  • Default properties
  • Interfacing function
  • Computational function
  • See also
  • Authors

Palette

• Sinks - Sinks palette

Dialog box

• In size
  Integer. Set the size of the regular input port.
  Properties : Type 'vec' of size 1.

• Output window number (automatic:-1)
  Integer. The number of graphic window used for the display.
  If default value is used, the scope automatically defines the output window number.
  Properties : Type 'vec' of size 1.

• Sampling period
  Scalar. The value of the sampling period.
  This value is used on x-axis to correctly display the frequency scale.
  If default value is used, the x-axis bound will be [0;0.5].
  Properties : Type 'vec' of size 1.

• Size of input buffer (FFT size)
  Integer. That parameter set the total size of the window to be displayed in number of samples and also the FFT size.
  Properties : Type 'vec' of size 1.

• Type of window (re:1, tr:2, hm:3; hn:4)
  Integer. This parameter is used for windowing FFT results.
  Properties : Type 'vec' of size 1.
  Possible choice are :
  • 1 Rectangular window.

  • 2 Triangular window.

  • 3 Hamming window.

  • 4 Hanning window.

• Size of the overlap buffer
  Integer. Set the overlap size. This gives the offset of each data window.
  This value must less or equal than the FFT size.
  Properties : Type 'vec' of size 1.

• Number of average
  Integer. Set the number of average before displaying FFT results.
  Properties : Type 'vec' of size 1.

• Axes scale flags [X,Y] (LIN:0, LOG:1)
  2 vector of integer. Set the scale of the X-axis and the Y-axis (linear or logarithmic).
  First integer is for the X-axis and the second for the Y-axis.
  Properties : Type 'vec' of size -1.

• Y axis units (U^2:0, dB:1)
  Integer. This parameter set the units of the y-axis.
  Properties : Type 'vec' of size 1.
  • 0 Power spectra density is expressed in term of the square unit of the input data.

  • 1 Power spectra density is expressed in dB.

• Y axis bound [min,max] (autoscale:-1)
  2 vector of real. Set the y-axis bounds of the scope.
  If default value is used, the scope automatically computes y-axis bound.
  Properties : Type 'vec' of size -1.

• Center Frequency (plot from DC:-1)
  Scalar. Define the middle (in frequency) of the displayed window.
  If default value is used, the result is displayed from the first sample of the FFT buffer.
  Properties : Type 'vec' of size 1.

• Denormalization Frequency (no:0)
  Scalar. Define a denormalization factor for the frequency scale of the X-axis.
  Properties : Type 'vec' of size 1.

• Display input buffer (no:0)
  Integer. (NOT YET IMPLEMENTED). With this parameters, one can display the input buffer before computation of FFT.
  Properties : Type 'vec' of size 1.

• Inherit (no:0, yes:1)
  Herits events by its regular input ports (disable the event input port).
  Properties : Type 'vec' of size 1.

Default properties

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

Interfacing function

• MODNUMCOS/macros/scicos_blocks/Sinks/PSPECSCOPE_c.sci [view code]

Computational function

• MODNUMCOS/routines/sinks/pspec_scope.c (Type 4) [view code]

See also

• EYESCOPE_c - Eye diagram scope block (Scicos Block)
• VECTORSCOPE_c - Vectorial scope block (Scicos Block)
• VECTORSCOPEXY_c - XY Vectorial scope block (Scicos Block)
• pspect_c - inter/cross correlation spectra computational routine (Low level routine)

Authors

INRIA Alan Layec