Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2009

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Why isn’t the increase in frequen

  • To: mathgroup at smc.vnet.net
  • Subject: [mg95582] Re: Why isn’t the increase in frequen
  • From: dh <dh at metrohm.com>
  • Date: Thu, 22 Jan 2009 06:59:21 -0500 (EST)
  • References: <gl722n$cai$1@smc.vnet.net>


Hi Tia,

look e.g. at fpr1: there it says that you only want a result if t<per1. 

But in Manipulate, you multiply the time by "a" (not the frequency as 

you may have intended).

hope this helps, Daniel



ratulloch at gmail.com wrote:

> Why isn't the increase in frequency/periodicity of this waveform not

> showing up tia sal2

> 

> Greetings All

> 

> I'm using the manipulate command to view what the wave form will look

> like will look like if I increase the frequency.

> But when I vary the variable =A1=A7a=A1=A8  to 3 the waveform only shows one

> complete wave instead of 3

> 

> Example I vary the variable =A1=A7a=A1=A8 to 3 it should show 3 waveforms

> repeating but instead it shows just 1 waveform in 1/3 the time.

> 

> Here=A1=A6s an image of what it's doing along with the code

> http://test.onewithall.net/math/waveform.jpg

> 

> Here's the code below:

> 

> tmin:=0

> tmax:=2 Pi

> per1=Pi;

> startPer1=0;

> fpr1[t_]:={Sin[Mod[t-startPer1,per1]+startPer1],startPer1<t<per1}

> 

> per2=2 Pi;

> startPer2=Pi;

> fpr2[t_]:={.3*Sin[Mod[t-startPer2,per2]+startPer2],startPer2<t<per2}

> 

> Manipulate[test=choice[Piecewise[{fpr1[(a*2 Pi)*(t-(phase/360/a))],fpr2

> [(a*2 Pi)*(t-(phase/360/a))]+c}],{t,tmin,tmax}],{{tmax,1,"t Time

> Scale"},0,5 Pi,1,Appearance=84_"Labeled"},{{a,1,"a Repeat Signal CPS"},

> 0,1000,1,Appearance=84_"Labeled"},{{phase,0,"Phase in degrees"},

> 0,-360,.5,Appearance=84_"Labeled"},{{c,0,"Offset C"},

> 0,-294,1,Appearance=84_"Labeled"},{choice,{Plot,Expand}}]

> 

> The reason why I'm doing this is that when I do periodic interpolation

> the

> Formula breaks down due to the Gibbs Phenomenon.  The signals I'm

> creating have

> about 200 separate values thats why it breaks down.  But I'm using a

> simple example to see if it can be done.  So I can basically stitch

> multiple simple wave signals together to create one big complex one

> and

> still have the ability to increase the frequency of the complex signal

> over time.

> 

> Is there another way I should be doing this?  I'm open to all

> suggestions

> 

> Tia sal2

> 




  • Prev by Date: Re: Re: Which editor do you use for math articles
  • Next by Date: Re: ï
  • Previous by thread: Re: Re: Re: Mathematica Animation Drives Me Crazy!
  • Next by thread: Re: ï