Mathematica 9 is now available
Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2009

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

Search the Archive

Re: How can I reduce the frequency of a sine wave tia sal22

  • To: mathgroup at smc.vnet.net
  • Subject: [mg104730] Re: How can I reduce the frequency of a sine wave tia sal22
  • From: Chris Degnen <degnen at cwgsy.net>
  • Date: Sun, 8 Nov 2009 06:46:06 -0500 (EST)
  • References: <hd3mup$9u7$1@smc.vnet.net>

On 7 Nov, 11:50, Rick T <ratull... at gmail.com> wrote:
> Greetings All
>
> I have the example below which produces 10 cycles
> a = Sin[10 x]
> Plot[a, {x, 0, 2 Pi}]
>
> What Type of signal would I need to add/multiple/divide to reduce it's
> signal/frequency to 5 cycles?  I know I can just change the number 10
> to 5
> but I need to combine it with another signal.  what mathematical
> operation/signal do I need to use.
>
> tia sal2

With a continuous, cyclic function it's a bit trivial:

a = Sin[10 x];
aim = Sin[5 x];
factor = (a + aim)/a - 1;
Plot[a*factor, {x, 0, 2 \[Pi]}]

For more complex cases you'd require deconvolution, e.g.
http://terpconnect.umd.edu/~toh/spectrum/Deconvolution.html

I'm looking forward to seeing any illustrative posts.




  • Prev by Date: Re: find subsets
  • Next by Date: Re: Can't figure out how to include syntax coloring in Printout
  • Previous by thread: Re: How can I reduce the frequency of a sine wave tia sal22
  • Next by thread: Clustering (question)