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too many combinations: Transition probability etc.

Started by John November 30, 2005
Hi

I am trying to do some statistics, but I don't know how to solve the problem 
I am working on.

I have N speech segments and I perform a 10th order LPC-analysis of each 
segment and get a 10-dimensional LPC-vector A(j)=[a1(j),a2(j),....a10(j)] 
for j=1 to N.

I then convert all A(j) to B(j)=[c1(j),c2(j),......,c10(j)] where the 
coefficients of B(j) are the LSF-coefficients corresponding to the 
LPC-vector A(j).

I want to figure out what:

- the probability of B(j) given B(j-1) is ? (transition probability)
- the probability of B(j) ?

How do I do that?

My thoughts:
The first step would be to define a discrete space S of outcomes for B(j), 
but the number of possible outcomes is very large. The coefficients of B(j) 
each
have a dynamic range from 0 to pi. If I use a discrete range from 
0,0.01,0.02,..........,3.14 that is 315 possible outcomes for any 
coefficient in B(j). Since B(j) is a 10-dimensional
vector I have 315^10 possible outcomes in the space S. That number is way 
too big to do any realistic computation in matlab......





John wrote:

> I am trying to do some statistics, but I don't know how to solve the problem > I am working on. > > I have N speech segments and I perform a 10th order LPC-analysis of each > segment and get a 10-dimensional LPC-vector A(j)=[a1(j),a2(j),....a10(j)] > for j=1 to N. > > I then convert all A(j) to B(j)=[c1(j),c2(j),......,c10(j)] where the > coefficients of B(j) are the LSF-coefficients corresponding to the > LPC-vector A(j). > > I want to figure out what: > > - the probability of B(j) given B(j-1) is ? (transition probability) > - the probability of B(j) ? > > How do I do that?
1. Calculate Pr[ B(j) | B(j-1) ]. 2. Calculate Pr[ B(j) ] = sum{k = 0 to N-1} Pr[ B(j) | B(k) ]
> My thoughts: > The first step would be to define a discrete space S of outcomes for B(j), > but the number of possible outcomes is very large. The coefficients of B(j) > each > have a dynamic range from 0 to pi. If I use a discrete range from > 0,0.01,0.02,..........,3.14 that is 315 possible outcomes for any > coefficient in B(j). Since B(j) is a 10-dimensional > vector I have 315^10 possible outcomes in the space S. That number is way > too big to do any realistic computation in matlab......
Don't quantize nearly so finely and use vector quantization rather than quantizing the individual elements. Ciao, Peter K.