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

Started by walala in comp.dsp14 years ago 5 replies

Dear all, I am studying some problem of the quantization error in customed designed quantization matrix for JPEG(the quantization matrix was...

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 the only model I can use in my prediction is "white noise", with variance to be (quantization_ste...


uneven quantization

Started by Anonymous in comp.dsp10 years ago 3 replies

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...

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

Started by Anonymous in comp.dsp12 years ago 1 reply

Hi, Can some one help me with deadzone quantization. What is its difference when compared to normal quantization methods? I googled on it...

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

Started by Anonymous in comp.dsp11 years ago

I want to implement the quantization technique in matlab for RLS and LMS design !! Please recommend something !! I know about the fixed point...

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

Started by professional in comp.dsp8 years ago

hello can any one help me on this vector quantization. i am working on a project of designing a vector quantization using matlab by...

hello can any one help me on this vector quantization. i am working on a project of designing a vector quantization using matlab by implementing idea of constructing the decission boundaries and reconstruction levels. does any one have algorithm for construction this. as i am a beginner in matlab this would really help me encouraging to learn matlab tool. thank you


Reference on quantization noise modeling

Started by Thomas Arildsen in comp.dsp9 years ago 4 replies

Does anyone know some examples where quantization is modeled by a linear model as follows: y = Q(x), modeled as y = a*x + q, where q is...

Does anyone know some examples where quantization is modeled by a linear model as follows: y = Q(x), modeled as y = a*x + q, where q is an additive noise, preferably white Gaussian. See the following paper for an example: Fletcher, A.; Rangan, S.; Goyal, V. & Ramchandran, K. Robust Predictive Quantization: Analysis and Design Via Convex Optimization Selected Topics in Signal Proc...


vector quantization

Started by geetanjali in comp.dsp11 years ago 1 reply

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

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


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

Started by Mr. Ken in comp.dsp10 years ago

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...

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 181/256. However the quantization of 181/256 causes system quantization error from 80dB to 30+dB, ...


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

Started by f1 fan in comp.dsp10 years ago 1 reply

> 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...

> 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 181/256. > However the quantization of 181/256 causes system quantization error from > 8


non-uniform quantization problem?

Started by Richard in comp.dsp12 years ago 9 replies

Hi all, I want to quantize Guassian distribution data use non-uniform quantization. And there are problems: How to determine the optimal...

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 multiply one non-uniform quantized data with a constant? Any suggestions will be appreciated! Best re...


Quantization Noise in FIR filters and SNR

Started by Rikard in comp.dsp11 years ago 6 replies

Hi, I have a problem understanding the effect of noise in fix-point FIR-filter implementations. Expecially SNR degradation due to large order...

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 filter will be: (Q^2/12)*N, where Q is quantization step and N is the order of the filter. ...


The optimal quantization

Started by st256 in comp.dsp5 years ago 3 replies

Hi, Anybody knows who and where works in optimal quantization area? Max Lloyd quantizer was created 50 years ago. What is going on this...

Hi, Anybody knows who and where works in optimal quantization area? Max Lloyd quantizer was created 50 years ago. What is going on this scientific direction now?


[Question] Quantization step size for DCT coefficients

Started by Anonymous in comp.dsp11 years ago

Hi, In any standard implementation of DCT, the DCT coefficients are quantized using Quantization Coefficients included in the JPEG...

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-quantization

Started by Kiran in comp.dsp11 years ago

Hi, In general, the reciever upto the demodulator uses uniform quantization and step size in the powers of 2 while the Low Density Parity...

Hi, In general, the reciever upto the demodulator uses uniform quantization and step size in the powers of 2 while the Low Density Parity Check (LDPC) decoder uses uniform quantiztion and arbitrary step size. LDPC decoder using min-sum algorithm needs different quantization schemes based on the offset used. Offset varies based on code parameters. Say the soft output of demodulator is 16...


Quantization Noise Current Spectral Density

Started by Barry in comp.dsp14 years ago 2 replies

Hi, I trying to calculate the Quantization Noise Current Spectral Density with regard to the ADC input of my system. My system includes a...

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)/6TR^2 where V is the voltage range at the ADC, Q is the number of bits - quatization, T is the...


how to understand noise shaping of sigma_delta in time domain?

Started by lxx.helen in comp.dsp9 years ago 6 replies

let's think of the noise shaping function for sigma-delta modulators. In frequency domain, we say quantization noise is pushed to higher...

let's think of the noise shaping function for sigma-delta modulators. In frequency domain, we say quantization noise is pushed to higher frequency and then removed by lowpass filter. what I wana do is to find a time domain understanding of this noise shaping function... start from the white assumption of quantization noise. I can imagine this is because we assume the quantization error rando...


How determine the path of signal?

Started by qaisar in comp.dsp12 years ago 6 replies

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...

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 determine the path which the signal is following between two consective quantization levels. i.e wea...


How Vector Quantization is a better compressin algorithm

Started by Anonymous in comp.dsp12 years ago 1 reply

Can anyone there inform me about how is vector Quantization is a better algorithm than other existing algroithm. If also possible provide...

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.


PDF of Quantization Error

Started by hschauhan in comp.dsp13 years ago 15 replies

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...

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


Quantizing the filter coefficients, what are the criterias?

Started by Mr. Ken in comp.dsp11 years ago 13 replies

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...

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