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1answer
122 views

Why use a 1-bit ADC in a Sigma Delta Modulator?

When looking at the discrete model of a Sigma-Delta Modulator as shown below, we can see that the quantizer is modelled as a white-noise source $e[n]$. From this model, we can derive the noise shaping ...
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2answers
52 views

Why is distorted / quantized white noise still white noise?

White noise can be created by setting every sample in the time domain to a random number with a gaussian distribution. Every sample is random, so the frequency response is obviously random. Easy ...
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2answers
61 views

Quantization level versus bandwidth [closed]

Why is it that increasing the number of quantization levels $L$ results in an increase in the signal's bandwidth?
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1answer
24 views

THD requirement for generated sine

I need to generate a sine signal using a DAC with a certain THD specification, say 0.1% @ 1KHz. As a first approach I’m considering it to be an ideal DAC along with an ideal LPF for aliasing removal ...
4
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2answers
56 views

What distribution is the easiest to compress?

I'm currently playing around with some compression algorithms and I'm asking myself if there is a type of data distribution / noise distribution that is easier to target with quantization (meaning ...
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0answers
16 views

What is wrong with my 3D DCT quantization?

I'm implementing 3D DCT quantization as in Quantization of 3D-DCT Coefficients and Scan Order for Video Compression (sorry about the paywall). They propose the following equation for generating the ...
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1answer
39 views

Harmonics in Quantal Histogram

I'm studying what I believe to be a system that produces a (noisy) quantal response (i.e. there should be a minimum increment of response). To do this, I've plotted a histogram of some ~6000 amplitude ...
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19 views

Optimal Channel Bit Allocation For Branches

The Question Hi. I was asked to solve this problem. I solved the part a but could not be able to solve the b part. Also found that $(\frac{2(1+p)^2}{(1+p)(1-p)})^2 = \frac{{{\sigma_\theta}_1}^2}{{...
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1answer
44 views

What information does the abs(normalized_image - normalized_quantised_image) carry?

Given a grayscale image X2 And its (under)quantised version with 3 bits depth X3 What information does the abs(X2_normalized - X3_normalized) carry?As an example ...
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0answers
15 views

Quantization of Image which have taken from partially less dark

I have picture with high resolution with 20M memory space and this image has been taken from the standing away from the window in room which has significantly less light as compared to outside. Image ...
3
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1answer
71 views

Why harmonic components appear only after a certain level when a signal is clipped?

I recently observed this phenomenon that when a signal is clipped the harmonics start to appear only after a certain level. The Python code to reproduce the effect is given below. The signal has 3 ...
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0answers
52 views

In µ law or A law companding, how reciprocal of the slope of compression curve is equal to quantum steps?

I was studying quantization and stepped on companding. The book I am following is Digital Communications by Simon Haykin. The book while discussing companding states that: For a given value of µ, ...
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0answers
71 views

How much will a low/high pass filter reintroduce quantization noise into a dithered signal?

For example, most audio signals are dithered prior to distribution. However, if a low or high pass filter is introduced after dithering or during playback, won't that negate some of the benefits of ...
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3answers
74 views

Is the incoming sample in a standard DPCM already quantized?

I began learning about DPCM and i've got one issue I am not sure about: Is the incoming sample m[k] (see image for reference) already quantizied or not? I think it is but with an (assumed) very fine ...
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0answers
18 views

Quantization used in amr-wb codec

What is the Quantization used in amr-wb speech codec? is there any matlab code or a detailed document (that contains the algorithm) to implement it?
0
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1answer
36 views

Correct way to quantize accelerometer data with microsecond precision?

I am analyzing large volumes of raw accelerometer data (~12 hours @ 200Hz) using Python. Some calculations (e.g. deriving Jerk) necessitate a time index with a regular interval. I have microsecond-...
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0answers
80 views

Which type of quantization is better?

If a signal's amplitude has a uniform PDF, which is better in the sense of producing a smaller quantization error: optimal scalar quantization or quantization with compressor (non-uniform quantization)...
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1answer
1k views

Compute SQNR (Signal to Quantization Noise Ratio)

I'm studying the quantization of an audio signal and in particular the SQNR (Signal to Quantization Noise Ratio). The book on which the study says that: where: N is the number of bits in the ...
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0answers
45 views

Modelling of quantization noise with logarithmic steps

I have to modell the quantization noise of ADC. I only know that the maximum relative error is 1 dB. Since this is logarithmic, I find it hard to formulate an appropriate model for the quantization ...
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1answer
30 views

Is it necessary to scale a signal for quantization noise analysis?

I am doing a series of tests to analyse the round-off (quantization) noise performance of single and two stage biquad cascades (direct form 1), at different sampling rates. The system I am simulating ...
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1answer
451 views

how to implement a one bit quantizer in simulink?

I am trying to implement a delta sigma modulator block diagram in matlab simulink but can't find a 1 bit quantizer (which is required in the modulator) anywhere . Could anyone please tell me how to go ...
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0answers
126 views

Quantization-Reducing resolution

I am a new student to DSP. I am using acceleration data and I want, for a particular reason, to reduce the resolution from 24bit to 16bit or 12bit. In MATLAB. Anybody out here with help
2
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1answer
158 views

What is the no overload region of a quantizer?

I was watching a video on quantization noise and the instructor kept referring to the "no overload" region of a quantizer? Could anyone please explain what that term means?
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1answer
78 views

Is there any literature discussing PDF after quantization?

Consider a random variable with a known distribution. I want to know if we quantized the variable the how the probability density function(PDF) would change? Specifically if the original PDF is ...
2
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1answer
678 views

Signal to Quantization Noise Ratio (SQNR)

I have this problem in my homework (following picture). How do find the signal to quantization noise ratio at the output? I don't want the solution. I just want to know a better approach to tackle ...
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3answers
441 views

why does quantisation noise sound like white noise?

To record sound and transform it to digital form, audio signals are recorded and its pressure levels are sampled and quantised. Why does quantisation noise sound like white noise?
3
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2answers
1k views

A query on the non-uniform quantization

I have read that non-uniform quantization boosts the smaller amplitude signals by a large amount. However the larger amplitude signals receive a small gain. As shown in the below diagram (Compressor ...
2
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1answer
528 views

Difference between clustering and quantization : Part 2

The Lloyd-Max quantizer is a scalar quantizer which can be seen as a special case of a vector quantizer (VQ) designed with the Linde Buzo Gray (LBG) algorithm. In k-means clustering, we are given a ...
3
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1answer
632 views

Lloyd Max quantization and clustering : Part 1

The Lloyd-Max quantizer is a scalar quantizer which can be seen as a special case of a vector quantizer (VQ) designed with the Linde Buzo Gray (LBG) algorithm. In k-means clustering, we are given a ...
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0answers
153 views

Sampling And Quantization

Any online resources from where we can practice Sampling and quantization problems. I am a btech student. We have been taught Sampling and quantization in Digital communication course and hence ...
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0answers
126 views

Should quantization use a step size of $1 / 2^N$ or $1/(2^N - 1)$?

I've been confounded by different quantization and reconstruction methods. I've always used the mid-tread method, with step size $1 / 2^N$, so for $8$ bits, ...
3
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2answers
217 views

DCT: Alternatives to quantization

When using the discrete cosine transform are there commonly used alternatives to quantization to decide which dct components to keep/are important? If not, how do people come up with quantization ...
1
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1answer
110 views

Proper rounding when converting between digitized values and floating point

I have some very large files that are unsigned 8 bit (0 to 255), real valued. I need to do some simple tuning and decimation. In the past, when I've dealt with low bit rate samples, I've run into ...
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1answer
910 views

Realize Simulink block “Ideal ADC Quantizer” in Matlab

Yesterday I posted following topic: "FFT alternates '0' for a quantized SIN wave". During post editing I was perturbed by some affair, I didn't formulate correctly the problem. So, my post was blocked ...
4
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1answer
95 views

Does delta-sigma ADC also reduce Gaussian noise on input signal to ADC or just quantization noise?

The motive for posing this questions arises from a difference of analysis between a colleague an myself. Our general environment is in the construction of an analog front-end which takes in signals ...
1
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1answer
58 views

For image quantization, is it necessary to sample image?

When we want to quantize an image, is it necessary to do sampling? When we know that image is a discrete signal, is it necessary to find the best samples with Nyquist rate?
0
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1answer
349 views

Quantization error in sampling

Consider the analog signal, $$x(t) = 2\cos(3000\pi t)+3\sin(4000\pi t)+7\cos(6000\pi t)$$ If the sampling rate is 8000 samples per second and quantized at 8 bits, find: Discrete values at any two ...
0
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1answer
5k views

Analog to digital conversion using Python

I'm a beginner. I try emulate analog signal conversion to digital (including sampling by time and quantizing by level) using Python. Here is my code: ...
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0answers
70 views

Filter output quantization - does this limit effective coefficient quantization?

I am implementing a filter in hardware, and the intended maximum data input is 16-bit. The question is, if the output is to be re-quantized to 16-bit, does this mean certain coefficients are ...
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1answer
415 views

Help using vector quantization

I have a sample signal, and I computed MFCC using this code.Now I have an array of 1225x12 size, where there are 12 coefficients for 1225 frames. Now I want to test another signal against this sample, ...
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2answers
137 views

Are time series data always contain noise?

I wonder if every time series data should contain noise or not. For example I am taking the price of a ticker, say Yahoo, every hour and noting the values. Does this data contains noise or not?
0
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1answer
131 views

Quantization SNR of bipolar signal

I want to estimate the SNR of a bipolar signal. I know that each bit increases the SNR at 6 dB. Do i have to subtract one bit for sign, so that for bipolar signals the SNR is (n-1) x 6 dB ?
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2answers
185 views

How does delta modulation work practically?

How does delta modulation work in practice? And where is it used? I find it confusing that, in 1-bit quantization we use only 2 level; if we apply this quantization, there will be loss in information. ...
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0answers
65 views

Dealing with quantization level limiting dsp

There is a analog signal in the form as below: $$ f(t)=A \sin(\omega(t) t+\phi)+B \sin(\omega(t-t_1) t+\phi_1) $$ Where $$B<<A$$ We are going to calculate $\phi, \phi_1, t_1 $,using dsp. But ...
0
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1answer
115 views

Cannot understand the attenuation in signal as the audio bit depth of adc changes

I am working on Active Noise Cancellation Project. I came across this strange problem, where the signal is getting attenuated as the audio bit depth changes and I cannot understand it! My circutit :I ...
0
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1answer
402 views

Uniform quantizer for gaussian input signal

I have a gaussian signal $x$ with zero mean and unit variance. I am quantizing it by using a uniform quantizer of step size $q$ calculated by $$q = \frac{x_\mathrm{max} - x_\mathrm{min}}{2^{M_\mathrm{...
5
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1answer
288 views

What is “hard quantization” strategy?

I am working on classification and several times I encountered with this term. What is hard quantization strategy? What does it differ from soft approach?
3
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2answers
79 views

Why are vector quantizers not used in video codecs?

Using a vector quantizer (VQ), groups of image samples (or motion compensated and/or transformed data) can be quantized as vectors. I'm curious about why VQs are not preferred in the modern, highly ...
1
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3answers
690 views

ensure stability against coefficient quantization

for a filter: $$ H(z)=\frac{1+0.1z^{-1}}{1+0.1z^{-1}+0.9998z^{-2}} $$ Which precautions could be taken to ensure that the filter does not become unstable because of coefficient quantization? I've ...
1
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1answer
7k views

Quantization Image using MATLAB

I'm trying to quantize an image 8 bits to 4 or 2-bits uniformly. I searched internet, interestingly I could not find what I want exactly. Then I wrote an simple code for it myself. I'm curious about ...