Jake wrote:
>>GO TO THE LIBRARY >> >>VLV >> > > > Great answer. > >
If you don't have enough time to go to library, you may want to refer the following paper: Vector quantization Gray, R.; ASSP Magazine, IEEE [see also IEEE Signal Processing Magazine] Volume 1, Issue 2, Part 1, Apr 1984 Page(s):4 - 29 Sorry if it was already mentioned. -James Gold
Jake wrote:
>>GO TO THE LIBRARY >> >>VLV >> > Great answer.
No, seriously -- you need to read up a little bit a good description of Vector Quantization. Remember that you replace *an entire vector* by an index in the codebook. Notice also that Vladimir did mention that you split the vectors into several components (I also suggested that earlier in the thread -- didn't your newsreader show my previous reply?). That is, if you have a 30-dimensional vector, then you can split it into three vectors, 10-dimensional each; now, you can use a codebook of, say, 8 bits, to encode each of the three vectors. The result is that you're using a total of 24-bits to encode each 30-dimensional vector. If the above does not clarify, then *really* you need to hit the books first, to get a general idea of the technique, and then we can give you a hand with any specific doubts you may have. HTH, Carlos --
> > GO TO THE LIBRARY > > VLV >

Jake wrote:

GO TO THE LIBRARY

VLV

>>It is the vector quantization of 10-dimensional LSF vector using the total >>of 20 bits for indexing the codebooks. > > > Thanks for a quick answer again :o) > > But I am sorry to say that I don't understand why you would need 20 bits for > indexing the codebooks....20 bits is a pretty high number and the codebook > wouldn't be that large??....So there is something I don't understand..... > > I read that a codebook usually contains 500 vectors. So wouldn't you need > 9 bits to represent an index range from 1 to 500??? > > Thanks again... > > > > >
> It is the vector quantization of 10-dimensional LSF vector using the total > of 20 bits for indexing the codebooks.
Thanks for a quick answer again :o) But I am sorry to say that I don't understand why you would need 20 bits for indexing the codebooks....20 bits is a pretty high number and the codebook wouldn't be that large??....So there is something I don't understand..... I read that a codebook usually contains 500 vectors. So wouldn't you need 9 bits to represent an index range from 1 to 500??? Thanks again...

Jake wrote:

>>To my knowledge, the best results for the LPC quantization are somewhere >>around 20 bits per vector. > > > This is just a guess: > > By 20 bits per 10-dimensional vector do you mean that you assign 2 bits per > coefficient in the 10-dimensional vector? >
No. It is the vector quantization of 10-dimensional LSF vector using the total of 20 bits for indexing the codebooks. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
> > To my knowledge, the best results for the LPC quantization are somewhere > around 20 bits per vector.
This is just a guess: By 20 bits per 10-dimensional vector do you mean that you assign 2 bits per coefficient in the 10-dimensional vector? This means that you assign a range from 0 to 3 to represent the dynamic range of the observed coefficient, right? The encoded vector would then be a 20 bit bit-stream looking like this: xx|xx|xx|xx|xx|xx|xx|xx|xx|xx| where "xx" is either 00,01,10 or 11 ....am I right?
> To my knowledge, the best results for the LPC quantization are somewhere > around 20 bits per vector.
Thanks for the quick answer, Vladimir However...I am quite new in this field of quantizing vectors....I am a bit puzzled by the "20 bits per vector"....Can you explain that in simple words? What do you mean by "20 bits per vector"? Thank you.