Re: Re: bode diagram

*To*: mathgroup at smc.vnet.net*Subject*: [mg57190] Re: [mg57151] Re: bode diagram*From*: DrBob <drbob at bigfoot.com>*Date*: Fri, 20 May 2005 04:43:26 -0400 (EDT)*References*: <d64fjl$9gl$1@smc.vnet.net> <200505190708.DAA13088@smc.vnet.net>*Reply-to*: drbob at bigfoot.com*Sender*: owner-wri-mathgroup at wolfram.com

Thanks! I think that explains the dips and bumps I was missing, compared to the website plots. Bobby On Thu, 19 May 2005 03:08:22 -0400 (EDT), Mariusz Jankowski <mjankowski at usm.maine.edu> wrote: > Bob, the argument of your function h must be I * s in both the magnitude > plot and the phase plot. You are therefore making a mistake in ALL of your > magnitude plots. > > Mariusz > > > >>>> DrBob<drbob at bigfoot.com> 05/14/05 5:15 AM >>> > I used the code below for each example at the link: > > http://www.swarthmore.edu/NatSci/echeeve1/Ref/Bode/BodeRules.html#Examples > > In several cases I got what appears to be the same result as pictured at the > link, but in other cases I got very different plots. The fourth example is > particularly strange. Am I doing this wrong? > > I'm plotting magnitude and phase on a single plot in each case, and I'm ONLY > plotting the exact curves -- assuming I have the right formulae for them. I > see no point in approximate plotting techniques, with exact plots readily > available. > > Needs["Graphics`Graphics`"] > SetOptions[LogLinearPlot, PlotStyle -> > {Red, Blue}, PlotRange -> All, > ImageSize -> 500]; > db = 20*Log[10, Abs[#1]] & ; > > Clear[h] > h[s_] = 100/(s + 20); > LogLinearPlot[{db[h[s]], Arg[h[I*s]]*(180/Pi)}, > {s, 1, 10^3}]; > > h[s_] = (100*s + 100)/(s^2 + 110*s + 1000); > LogLinearPlot[{db[h[s]], Arg[h[I*s]]*(180/Pi)}, > {s, 10^(-2), 10^4}]; > > h[s_] = 10*((s + 10)/(s^2 + 3*s)); > LogLinearPlot[{db[h[s]], Arg[h[I*s]]*(180/Pi)}, > {s, 10^(-1), 10^3}]; > > h[s_] = (-100*s)/(s^3 + 12*s^2 + 21*s + 10); > LogLinearPlot[{db[h[s]], Arg[h[I*s]]*(180/Pi)}, > {s, 10^(-2), 10^3}]; > > h[s_] = 30*((s + 10)/(s^2 + 3*s + 50)); > LogLinearPlot[{db[h[s]], Arg[h[I*s]]*(180/Pi)}, > {s, 10^(-1), 10^3}]; > > h[s_] = 4*((s^2 + s + 25)/(s^3 + 100*s^2)); > LogLinearPlot[{db[h[s]], Arg[h[I*s]]*(180/Pi)}, > {s, 10^(-1), 10^3}]; > > Bobby > > From: Pratik Desai <pdesai1 at umbc.edu> To: mathgroup at smc.vnet.net > References: <200505120633.CAA08967 at smc.vnet.net> > > David Park wrote: > >> I'm fairly certain it could be done with Mathematica if you would only > tell >> us what a bode diagram is and give us some sample data of function that > you >> want to plot in the diagram. >> >> David Park >> djmp at earthlink.net >> http://home.earthlink.net/~djmp/ >> >> From: GaLoIs [mailto:lanellomancante at inwind.it] To: mathgroup at smc.vnet.net >> >> >> hi, like plotting simple bode diagrams of systems. could you give me some >> information about it? i can do it with another program, but i'd like to > see >> how mathematica works >> thank you >> >> >> >> >> >> >> > Here is a nice example from a website I found. > > *http://www.swarthmore.edu/NatSci/echeeve1/Ref/Bode/Bode.html* > > -- DrBob at bigfoot.com

**References**:**Re: bode diagram***From:*"Mariusz Jankowski" <mjankowski@usm.maine.edu>