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Generalized Complex Signal Power

The net complex power involved in the propagation can be defined as [4]

$\displaystyle {\cal P}$ $\textstyle =$ $\displaystyle {\mbox{\boldmath$u$}}^* {\mbox{\boldmath$p$}}\, = \, ({\mbox{\bol...
...+ {\mbox{\boldmath$u$}}^-)^* ({\mbox{\boldmath$p$}}^++ {\mbox{\boldmath$p$}}^-)$  
  $\textstyle =$ $\displaystyle {{\mbox{\boldmath$u$}}^+}^{*}{\mbox{\boldmath$R$}}{\mbox{\boldmat...
...+- {{\mbox{\boldmath$u$}}^-}^{*}{\mbox{\boldmath$R$}}^*{\mbox{\boldmath$u$}}^-+$  
    $\displaystyle {{\mbox{\boldmath$u$}}^-}^{*}{\mbox{\boldmath$R$}}{\mbox{\boldmat...
...^+- {{\mbox{\boldmath$u$}}^+}^{*}{\mbox{\boldmath$R$}}^*{\mbox{\boldmath$u$}}^-$  
  $\textstyle \stackrel{\triangle}{=}$ $\displaystyle ({\cal P}^+- {\cal P}^-) + ({\cal P}^\times - {\cal P}^{\times*})$ (16)

where all quantities above may be functions of $z$, and ``$*$'' denotes paraconjugation (transposition and complex conjugation on the unit circle in the $z$ plane). The quantity ${\cal P}^+=
{{\mbox{\boldmath$u$}}^+}^{*}{\mbox{\boldmath$R$}}{\mbox{\boldmath$u$}}^+$ is called right-going active power (or right-going average dissipated power4), while ${\cal P}^-= {{\mbox{\boldmath$u$}}^-}^{*}{\mbox{\boldmath$R$}}^* {\mbox{\boldmath$u$}}^-$ is called the left-going active power. The term ${\cal P}^+- {\cal P}^-$, the right-going minus the left-going power components, we call the net active power, while the term ${\cal P}^\times - {\cal P}^{\times*}$ is net reactive power. These names all stem from the case in which the matrix ${\mbox{\boldmath$R$}}(z)$ is positive definite for $\vert z\vert \geq 1$. In this case, both traveling components of the active power are real and positive, the active power itself is real, and the reactive power is purely imaginary.


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Download wgj.pdf

``Aspects of Digital Waveguide Networks for Acoustic Modeling Applications'', by Julius O. Smith III and Davide Rocchesso , December 19, 1997, Web published at http://ccrma.stanford.edu/~jos/wgj/.
Copyright © 2007-02-07 by Julius O. Smith III and Davide Rocchesso
Center for Computer Research in Music and Acoustics (CCRMA),   Stanford University
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