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any good model for quantization error? how to design my quantization matrix?

Dear all, I am studying some problem of the quantization error in customed designed quantization matrix for JPEG(the quantization matrix was designed by me, so it is worse than standard JPEG in terms of quality). I am trying to design a filter to remove these error due to quantization. Current...

uneven quantization

I would like to know how can I make an uneven quantization !! I would like to get straight lines (approximation of the random curve) !! It is some sort of quantization where I have also average it !! Can anybody help ? Thanks Ali ...

newbie question on deadzone quantization

Hi, Can some one help me with deadzone quantization. What is its difference when compared to normal quantization methods? I googled on it resulting unsatisfactory results :( Is there a place on the web I can look for more information regarding the same. -- TIA, jag ...

quantization for RLS and LMS design

I want to implement the quantization technique in matlab for RLS and LMS design !! Please recommend something !! I know about the fixed point toolbox to do quantization !! Please tell me where can i get it and for free !! dont tell me mathswork cause it sucks !! ...

vector quantization

is dct necessary to quantize an image? can the intensity value of each pixel be directly used for quantization? ...

Re: IIR filter stability issues

srikar.ebe@gmail.com wrote: > Hi, > It would very helpful if someone could tell me how to test for the > stability of an IIR filter.(i.e the stability problems related to the > implementation-due to availability of only finite precision) > > thanks > srikar > There are two probl...

Re: Audio Low Frequency Instability

On Nov 8, 6:31 am, Dirk Bruere at NeoPax wrote: > Can anyone point me to the reasons why IIR peaking filters become > unstable at low audio frequencies? Quantization of arithmetic leads to quantization of how much any coefficient can affect the results. Quantization of the IIR coeffici...

Quantization Noise Current Spectral Density

Hi, I trying to calculate the Quantization Noise Current Spectral Density with regard to the ADC input of my system. My system includes a C6711 DSK and an AIC23EVM Codec. I think I'm right in saying that the formula for Quantization Noise Current Spectral Density is given by - ((V/2^Q)^2...

How would one minimize quantization error in radix-8 based FFT?

My design is 4096-point FFT, which splits into 4 stages of radix-8 FFT. The system twiddle factor is 15-bits and gives acceptable quantization error. However the design is bogged down by the trivial twiddle factor within radix-8, W81 = 2 * pi * 1/8 = 0.707, which can be reasonably done with 181...

non-uniform quantization problem?

Hi all, I want to quantize Guassian distribution data use non-uniform quantization. And there are problems: How to determine the optimal quantization level. Is there any reference? How to add two non-uniform quantized data? Shall I convert it back to uniform quantized data. How to multi...

RE: How would one minimize quantization error in radix-8 based FFT?

> My design is 4096-point FFT, which splits into 4 stages of radix-8 FFT. > The system twiddle factor is 15-bits and gives acceptable quantization > error. > However the design is bogged down by the trivial twiddle factor within > radix-8, > W81 = 2 * pi * 1/8 = 0.707, which can be reasona...

[Question] Quantization step size for DCT coefficients

Hi, In any standard implementation of DCT, the DCT coefficients are quantized using Quantization Coefficients included in the JPEG file stream. Here where is the Quantization step size ? Do they vary in MPEG files Is it 2^(M-1) ? Is it M = 10. for JPEG files James Colin ...

Re: Theoretically Highest Quality of PCM Audio

In article 20031121215550.28390.00000721@mb-m14.aol.com, BobGardner at bobgardner@aol.com wrote on 11/21/2003 21:55: > > > > If I am given a 16-bit fixed-point number of uniform quantization, I > > can surely say that the maximum theoritic dynamic range I can get is > > 96.329 dB > ...

mu-law companding

hi all, I'm doing some tests with mu-law companding. I have a speech signal with Fs = 16 kHz, 16-bit. I test on 2 methods to encoding in 8/4/2 bit: - 1st methode: using uniform quantization 256/ 16/ 4 levels. - 2nd methode: using mu-law to compand sigal before, then using uniform quantization ...

Quantizing the filter coefficients, what are the criterias?

I am quantizing an FIR filter's coefficients into 8-bit signed integers, which will be coded into hardware. How do I describe the errors in the quantization in my report? I only know of frequency response before and after quantization. TIA ...

How determine the path of signal?

I am digitizing the sampled signal be using a uniform quantizer, so the step (q) between two consective quantization levels is fixed and is "q = Vin/2^N" where 'q' is the quantization step, 'Vin' is the total range of quantizer and 'N' are the effective number of bits of quantizer. Now I want to ...

Re: Purpose of interpolation in DACs?

Hi Ben, I think your analysis so far is correct. There is another reason for upsampling a signal to a DAC: to increase the effective resolution of the DAC. In order for this to work, your digital signal resolution must be wider than the DAC resolution. For example, if your digital signal wa...

How Vector Quantization is a better compressin algorithm

Can anyone there inform me about how is vector Quantization is a better algorithm than other existing algroithm. If also possible provide me with a comparative analysis of it. Is it better to implement the algorithm using C language. ...

Re: Nyquist Didn't Say That

Tim Wescott wrote: > > > Because I'm a mercenary. > > Posting to wikipedia doesn't pay directly, nor does it give me public > credit. While it benefits the world it doesn't lead to me getting any > checks in the mail. I share that pure cynical point of view and consider my...

PDF of Quantization Error

Hello! I am newbee in DSP and am reading the book by Steven Smith. In chapter three, the PDF of quantization error is not a gaussian. And I am wondering why? The errors are random then why isn't it a gaussian? Can somebody help me on this? Thanx in advance Regards --Himanshu ...

application of vector quantization on cepstral coefficients

please give me examples of cepstral coefficients in speech recognition .and how we can apply vector quantization on it. ...

IIR quantization

In the matlab filter design filter box, when I click the Quantization button after design a IIR, the freq response seems very different. I cannot find the place where you can configure how many bits for the system? Where do you specifiy that you are using a 16bit or 32bit system? thanks An...

Quantization Noise in FIR filters and SNR

Hi, I have a problem understanding the effect of noise in fix-point FIR-filter implementations. Expecially SNR degradation due to large order filter. The maxum error I will experience after quantization will be: e=sum(abs(Q(h(n))-h(n))) The round off power from the Coeff for the whole...

Scaling coefficients (real to integer)

First, let me qualify this post by stating that I am not a DSP expert - most of my work is implementing the signal processing, not designing the signal processing. I just finished reading Mr. Yates' document "Practical Considerations in Fixed-Point FIR Filter Implementations" (http://www.digita...

Question about quantization

I've got transfer function H(z) and determined location of poles and zeros. How can I recalculate location of poles and zeros using a minimum quantization level of 0.125 for direct form II, cascade, and parallel structures? Where can I find sample solutions for similar problems? Any online tu...

Dithering for

Hopefully some of you guru's here can set me straight here. In an attempt to reduce quantization spurs, I have read about dithering. I have seen wideband dithering and narrowband dithering. All of this is done in the analog domain prior to the sampling. My question is: Why can we not simpl...

Re: Questions about equivalents of audio/video and digital/analog.

Floyd L. Davidson wrote: > Jerry Avins wrote: > > Floyd L. Davidson wrote: > > > > ... > > > > > Nyquist rate: > > > The reciprocal of the Nyquist interval, i.e., the > > > minimum theoretical sampling rate that fully > > > describes a given signal, i.e., ena...

Re: Fixed Point DSP Vs Floating Point DSP

In article , sandeep_mc81@yahoo.com says... > Hi, > > I searched the internet to find out the difference between a fixed > point & a floating point DSP. > To my surprise, I did not find a well defined difference. > > Plz, can anyone differentiate between the two so that a l...

Translations to French

I have to write a one-page French abstract of my thesis, and I'm having trouble finding the French translation of several terms. If someone out there could help me out with the following terms: Vector Quantization Codebook (in the context of vector quantization) Lossy data compression C...

IIR filter coefficient quantization newbie

I designing a IIR digital filter with the following parameters (Fs = 500k,fc = 1k,fs = 10k,wc = 1db,ws = 40db} using matlab. And I got the following coefficient using the following .m file. A1 A2 B2 B0 B1 { -1.9725 0.9733 0.0001 0.0001 0.0001 ...

Re: Understanding Digital Signal Processing by Richard Lyons

Randy, This was related to SNR from 16-bit quantization, and useful dynamic range limited by the quantization. Both claims made simultaneously. Dirk quantization noise on the the SNR and Randy Yates wrote: > "dbell" writes: > > [...] > > Hey Dirk, > > I was tracking you r...

Vector Quantization query

Hi, I'm currently coding an adaption of the LBG vector quantization algorithm. At the point where you have attributed each vector to one of the code vectors, you must calculate the centroid of those vectors to become the new centroid of the code vectors. My question is this. If no vecto...

Re: Digital filter simulators?

Hello Tim, > > I'm not sure what you mean by 'level select'. > It is the determination of how much energy there is in one frequency range versus the others. There can also be nothing there, just unwanted spectra or noise. The level of the input signal is not known except that it wil...

Re: What to look for in DAC

fEIT wrote: > Hi all, > > Can some one advice me to choose a DAC what parameters I should look > for in the data sheet? That must depend on what parameters are important for the job you want to use the DAC for. > Also what is the relation between the SNR and the DAC resolution > ...

Re: Question about audio artifacts; WMA vs. MP3

On Aug 17, 3:45 pm, Richard Dobson wrote: > > As I said before, I tried my WMA/MP3 experiment with many different > > audio softwares. The results were the same. > > Could be piled-up dither? Don't MPEG Layer 3 encoders usually include an adaptive quantization step? If so, any noi...

Wave-to-Wave Recording. Noisy on Low Volume!

Why is it whenever I record from one wave file - at an extremely low volume - another wave file, I get noise? The process is completely digital. There is no analog, no D-A, and no A-D. Why the #%!$@%!@# is their noise? Since this is not analog-to-digital, this is obviously *not* quantizatio...

Re: IIR filter question

Martin Eisenberg wrote: > Joerg wrote: > > > > I am no expert either but from what I have seen IIR is still > > used, often with some added measures to muffle their inherent > > instability upon signal loss. > > > What do you mean by "instability upon signal loss"? > (snip) ...

Re: Delta-sigma ADC question

Ville Voipio wrote: > > Actually, it would be more precise to talk about "oversampling" > converters, because that's what makes the difference. Not the > actual converter topology or modulator order. > > - Ville > Not exactly. The pole in the feedback loop of a delta-sigma conve...

Re: Understanding bit widths requirements in Sigma Delta Modulators

On May 22, 9:10 pm, Tim Wescott wrote: > somdeb wrote: > > I am trying to understand how bit-width requirements at different > > integrators can be estimated... couldn't find much in literature. ... > > As a guess, I'd say it has to be big enough so that, at a minimum, the > quanti...

Sigma Delta Modulation - SNR calculation

Hello All, I have created a simple routine in MATLAB that simulates a second order sigma delta modulator. I am now trying (with some difficulty) to calculate the SNR of the modulator given sinusoidal inputs. My understanding of how this procedure should be carried out is as follows, 1) Build...