Re: ï

*To*: mathgroup at smc.vnet.net*Subject*: [mg95620] Re: ï*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Thu, 22 Jan 2009 07:15:12 -0500 (EST)*Organization*: Uni Leipzig*References*: <gl722n$cai$1@smc.vnet.net>*Reply-to*: kuska at informatik.uni-leipzig.de

Hi, because your Piecewise[] functions are not periodic, i.e., the interval where the piece is defined is not Mod[_,somePeriod] Regards Jens 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 >