Talk:Discrete cosine transform
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[edit] Change in notation
I have started converting the notation in this article to match the changes that have been made to Discrete Fourier transform . The four changes are:
1. n becomes N: Change all instances of the symbol n to the new symbol N to represent the length of the sequences in both the time and frequency domains.
2. k becomes n: Change all instances of the symbol k to the new symbol n to represent the index variable for the time domain sequence.
3. j becomes k: Change all instances of the symbol j to the new symbol k to represent the index variable for the frequency domain sequence.
4. f becomes X: Change all instances of the symbol f to the new symobl X to represent the transformation of the data sequence in the frequency domain.
For more information, see Talk:Discrete Fourier transform.
-- Metacomet 16:09, 6 January 2006 (UTC)
I just tried typing in the formula for the DCT 2 and 3 into my compiler to see what would happen. It wasn't inverting properly. It looks like it should be $-\frac{1}{2} x_0$ instead of positive. Adding in the negative sign made it work for me.
- Nope, you must have mistyped them, or have a bug in your program. (To see that your proposed minus sign isn't correct, consider the simple case of a transform of all 1's.) —Steven G. Johnson 22:15, 1 September 2006 (UTC)