# Are there transfer function, state space, and bode plots?

I am looking for something like tf(), ss(), and bode() in control package of Octave, but I don't see them in sage. Are there any equivalents?

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las bases teóricas-matematicas son la equivalencia que buscas

( 2014-08-20 21:29:42 +0200 )edit

I'm sorry, but I can read nothing other than English and Chinese...

( 2014-08-20 23:58:33 +0200 )edit

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There seems to be something like that in numpy/scipy, I will check that out.

UPDATE: Now I use Sage/Sympy to derive the symbolic function, and convert the numerator and denominator to coefficients of polynomials, and create LTI systems in Scipy to use functions like LTI.bode(), signal.convolve(), etc. Also, I really can't read most of your answers.

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Luis Ratia has made some Sage notebook worksheets available: Bode plots, and just recently posted about it on the sage-support and sage-notebook Google groups.

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Thanks, but I know how to do that. I am just not sure if there is an automatic way to help me do the s=I*omega and 20*log(abs(H),10) etc.

( 2014-08-20 20:19:38 +0200 )edit

En Sage, la graficas son exactas y las unidades son en decibelios en el eje de salida y radianes en la grafica de magnitud, en la fase son grados en el eje y y radianes en el eje x, en las dos graficas el eje x es semilogaritmico. Yo comparo estas con los libros de control automatico y los resultados son totalmente compatibles.

Edit: translation. In Sage, the graphics are exact and the units are decibels on the output axis and radians for the magnitude; in the phase, degrees in the $y$-axis and radians in the $x$-axis; in both graphics the $x$-axis is semilogarithmic. I compare these with books on automatic control and the results are fully compatible.

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Sorry, I can't read this...

( 2014-08-20 17:27:26 +0200 )edit

I know how to plot if I type in the function manually. I am just trying to find a way so that I don't need to type lots of 20*log(abs(H),10) or H.subs(s=I*omega) things, they are all repetitive.

( 2014-08-20 20:18:12 +0200 )edit

pues no se si son repetitivas, se define G(s) una ves y luego a partir de esa funcion se obtienen las graficas. Una solución es crear una funcion sage y pasarle a G(s) como argumento, esta funcion sage retorna las graficas de bode y nyquist, o grafica polar, tambien puedes obteber la de Nichols.

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Asked: 2014-08-20 15:06:30 +0200

Seen: 2,279 times

Last updated: Aug 22 '14