On 9/15/2010 10:44 AM, Invisible wrote:
>>> So for every pair of samples, it simply computes the sum and the
>>> difference?
>>
>> Recursively, yes...
>
> Right. Well if you say "it calculates the sum and the difference of each
> pair of samples", suddenly it becomes pretty obvious what it's doing,
> and why it's reversible.
>
> It also explains why the partial reconstructed wave is the shape it is.
> And it suggests that having fewer terms available is going to futz with
> the high frequencies first.
>
> (Then again, this sort of transform is probably more useful for
> time-domain signals like image data rather than frequency-domain data
> like sound.)

Right! But, the trick also gives better frequency resolution at lower 
frequencies, simply because of the subsampling that takes place.

-- 
~Mike

Post a reply to this message