I understand that you perform the inner products of the signal with the wavelet and the scaling functions to get the coefficients. But I have two questions about the prcoess: 1. Do I perform the products of all three variables (ie: signal.scaling.wavelet) to get the coefficients, or do I perform two separate calculations (ie: signal.scaling and signal.wavelet)? 2. What values of the signal do I use in the calculation (ie: do I use the frequency, the amplitude, the phase, etc.)? Any help will be much appreciated. David Saunders

# calculating daubechies coefficients

Started by ●October 22, 2004

Reply by ●October 22, 20042004-10-22

DavidSaunders9 wrote:> I understand that you perform the inner products of the signal with > the wavelet and the scaling functions to get the coefficients. But I > have two questions about the prcoess: > > 1. Do I perform the products of all three variables (ie: > signal.scaling.wavelet) to get the coefficients, or do I perform two > separate calculations (ie: signal.scaling and signal.wavelet)?If the context of your question is a sampled data system, I would say here that you perform two convolutions. The convolution is a running inner product. For each new sample, you form the two inner products with the last n samples to get the next two coeficients.> > 2. What values of the signal do I use in the calculation (ie: do I > use the frequency, the amplitude, the phase, etc.)?The last n discrete sample values where n is the length in samples of your wavelet and your scaling function. Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein

Reply by ●October 23, 20042004-10-23

Thank you for your reply, but I am still a bit confused. In an example calculation I read it referred to the signal as being [3,1,-2,4]. Are these four numbers the values of the sample at t = 0, 1, 2, 3? Bob Cain <arcane@arcanemethods.com> wrote in message news:<clbir202dcf@enews4.newsguy.com>...> DavidSaunders9 wrote: > > I understand that you perform the inner products of the signal with > > the wavelet and the scaling functions to get the coefficients. But I > > have two questions about the prcoess: > > > > 1. Do I perform the products of all three variables (ie: > > signal.scaling.wavelet) to get the coefficients, or do I perform two > > separate calculations (ie: signal.scaling and signal.wavelet)? > > If the context of your question is a sampled data system, I > would say here that you perform two convolutions. The > convolution is a running inner product. For each new > sample, you form the two inner products with the last n > samples to get the next two coeficients. > > > > > 2. What values of the signal do I use in the calculation (ie: do I > > use the frequency, the amplitude, the phase, etc.)? > > The last n discrete sample values where n is the length in > samples of your wavelet and your scaling function. > > > Bob

Reply by ●October 23, 20042004-10-23

DavidSaunders9 wrote:> Thank you for your reply, but I am still a bit confused. > > In an example calculation I read it referred to the signal as being > [3,1,-2,4]. Are these four numbers the values of the sample at t = 0, > 1, 2, 3?If that's what they called the signal, then yes. BTW, I highly recommend "Wavelets and Filter Banks" by Strang and Nguyen as a pedagogic resource. Bob -- "Things should be described as simply as possible, but no simpler." A. Einstein