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.