Scicos Block
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Phase noise computation of a modulated Delta-Sigma fractionnal divider block

Contents

• Phase noise computation of a modulated Delta-Sigma fractionnal divider block
  • Palette
  • Description
  • Dialog box
  • Default properties
  • Interfacing function
  • Computational function
  • Authors
  • Bibliography

Palette

• Pll - Phase Locked Loop palette

Description

This block computes the phase error of a Delta-Sigma fractionnal N+K/M frequency divider.
It ouput is given by :

$$\begin{eqnarray} \delta \tilde{\phi_{\rm DSM}}(k)=\frac{2\pi}{NM} \left(M\sum^{k}_{i=1}\left({\rm DSM}(i-1)+{\rm DSM}(i)\right) - k{K}\right) \end{eqnarray}$$

with N, the divider factor, K/M fractionnal divider factor and DSM() the ouput of a Delta-Sigma modulator.

Dialog box

• K
  The numerator of the fractionnal value of the divider factor.
  Properties : Type 'mat' of size [-1,-2].

• M
  The denominator of the fractionnal value of the divider factor.
  Properties : Type 'mat' of size [-1,-2].

• Inherit (no:0, yes:1)
  Inhérits events by its regular input.
  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 3
  
• regular outputs:
  - port 1 : size [1,1] / type 3
  
• number/sizes of activation inputs: 0
• number/sizes of activation outputs: 0
• continuous-time state: no
• discrete-time state: no
• object discrete-time state: no
• name of computational function: perrdsm

Interfacing function

• MODNUMCOS/macros/scicos_blocks/Pll/PERRDSM_c.sci [view code]

Computational function

• MODNUMCOS/routines/pll/perrdsm.c (Type 4) [view code]

Authors

A. Layec

Bibliography

[1] B. D. Muer and M. S. Steyaert, ``On the analysis of sigmadelta fractional-n frequency synthesizers for high spectral purity,'' IEEE Trans. Circuits Syst. II, vol. 50, no. 11, pp. 784-793, Nov. 2003.