# Do number series represent sine wave?

• 01-17-2012, 03:03 PM
rng
Do number series represent sine wave?
I have a set of about 1000 numbers which if plotted may produce a sine wave pattern (a series of sine waves in continuity). How can I find out if these numbers represent sine wave pattern using java?

• 01-17-2012, 04:33 PM
KevinWorkman
Re: Do number series represent sine wave?
How would you do this by hand, without a computer?
• 01-17-2012, 05:08 PM
rng
Re: Do number series represent sine wave?
I can only think of plotting a graph and seeing it !
• 01-17-2012, 05:38 PM
JosAH
Re: Do number series represent sine wave?
Try an autocorrelation (google is your friend here) on the signal and the signal itself, shifted n samples. For the value of n where the correlation is at its maximum you have found the frequency of the sine, i.e. n*st where st is the sample time.

kind regards,

Jos
• 01-17-2012, 05:45 PM
rng
Re: Do number series represent sine wave?
• 01-18-2012, 10:33 AM
rng
Re: Do number series represent sine wave?
It is surprising that one needs complex programs and algorithms to identify even simple shapes. Is there any simple method to differentiate between 2 sets of points which on plotting show simple shapes of V and U respectively.
• 01-18-2012, 10:38 AM
JosAH
Re: Do number series represent sine wave?
Quote:

Originally Posted by rng
It is surprising that one needs complex programs and algorithms to identify even simple shapes. Is there any simple method to differentiate between 2 sets of points which on plotting show simple shapes of V and U respectively.

Try the NN aproach (Neural Network). A BAM (Bidirectional Associative Memory) or Kohonen network are quite suitable. Hopfield networks have too low storage capacity for image recognition. Beware though: this isn't trivial and maybe, after you've struggled your way through it, you'll appreciate simple eyes and the brain's processing power ;-)

kind regards,

Jos
• 01-18-2012, 12:04 PM
rng
Re: Do number series represent sine wave?
Thanks for your suggestions. Can you recommend some website/software to quickly get started in using neural networks for simple problem like I stated above?
• 01-18-2012, 01:16 PM
JosAH
Re: Do number series represent sine wave?

kind regards,

Jos
• 01-18-2012, 01:33 PM
Tolls
Re: Do number series represent sine wave?
Quote:

Originally Posted by rng
It is surprising that one needs complex programs and algorithms to identify even simple shapes.

Took evolution rather a long time to develop such pattern recognition...
• 01-18-2012, 04:05 PM
JosAH
Re: Do number series represent sine wave?
Quote:

Originally Posted by Tolls
Took evolution rather a long time to develop such pattern recognition...

A spider can grow new lenses for their eyes overnight; I wonder why they lose them every day; stupid little animals ...

kind regards,

Jos
• 01-18-2012, 04:36 PM
Tolls
Re: Do number series represent sine wave?
Think of them like disposable contact lenses.
See?
Nature's waay ahead of us on these things.
• 01-18-2012, 04:46 PM
JosAH
Re: Do number series represent sine wave?
Quote:

Originally Posted by Tolls
Think of them like disposable contact lenses.
See?
Nature's waay ahead of us on these things.

Obviously there are no feriocious spider eaters active during the night; lazy bums, those spider eaters ... nature is kind of stupid ...

kind regards,

Jos