Questions tagged [scaling]

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Scaling issue after doing manipulations in FFT

I have two filters which must apply (in series) to same input data $x[n]$ e.g of length 256 (real time asio input buffers). One filter is e.g. an impulse response $h_1[n]$ of a speaker and other one ...
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20 views

How can single low-resolution have multiple high-resolution versions?

I'm trying to prove the fact that the super-resolution problem is an ill-posed problem. Having a single low-resolution image, we can generate multiple high-resolution images. Which also known by ...
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9 views

Wavelet Analysis Magnitude Scale

I am trying to plot magnitude against frequency averaged over a time window. To do this I make a morlet wavelet Filterbank. And multiply the dft of each kernel by the dft of my incoming data set. ...
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81 views

Why is noise a power signal?

1. I'm generating a power signal: ...
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1answer
39 views

What's the right scale to represent a frequency spectrum?

To represent a 16 bits temporal spectrum, it's "easy" : my scale is going from -32000 to +32000. But What's the scale for a frequency spectrum ? I made that try : I calculated a pure single frequency ...
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1answer
167 views

Overlap/add time-domain audio frames: How does normalization/scaling work with overlap greater than 50%?

I am attempting to overlap-add time-domain audio frames in a real-time context (with a continuous stream of data coming-in). Each frames consist of 1024 samples and have been previously "Hann" ...
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1answer
45 views

what is multiresolution

I have gone to wavelets course and up to my knowledge, changing the scale and translation of wavelets produces multiresolution images. is this correct or can someone tell me what is multiresolution ...
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2answers
99 views

How to scale a signal to get desired variance [duplicate]

I am new to dsp, and I'd really appricate it if someone please help me with this problem. I guess it's a basic simple question, but I cannot get it write. Here is the question: The variance of a ...
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0answers
135 views

Correctly scaling Power Spectrum and Correlation Function of Galaxies from Mock Catalogues

I'm currently writing a code to compute the two-point correlation function of a set of galaxies. As I work with a loooot of galaxies, it was suggested to me not to do it in real space, but to compute ...
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1answer
51 views

Most natural interpolation to simulate increasing distance?

Background: I'm generating multiple datasets with varying scales of resolution to simulate taking pictures from varying distances and then comparing image classification performances. For example ...
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3answers
900 views

Theoretical Maximum of DFT

For any discrete input signal between +1 and -1, what is the theoretical maximum DFT? If the input is a cosine of $N$ samples with amplitude $A$, the peak spectral magnitude is $A*N/2$. But what ...
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1answer
633 views

Digital 16-bit PCM audio signal scaling and STFT spectogram amplitude

I'm sampling a 16-bit PCM audio signal at 44100 Hz and I'm trying to understand the amplitude level of both the digital audio signal and its corresponding spectrum. The final goal is creating audio ...
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1answer
273 views

How to upscale an image without affecting pixel aspect ratio?

For example, if we upscale an image from 100 x 100 to 400 x 300 then we see the pixel stretch in the image which I want to eliminate. The easiest way I could think is to crop the image to maintain ...
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1answer
731 views

How to “scale” the FFT when using it to calculate discrete convolution?

As you probably know, the discrete convolution $ H = F \ast G $ of some $ F \left[ x \right] $ and some $ G \left[ x \right] $ can be calculated using the Fast Fourier Transform (FFT). To do this, ...
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1answer
97 views

signal saturation [duplicate]

My signal is an actuator displacement signal. It is a sinusoidal signal with the max amplitude of 10cm. I want to clip amplitude at 7 cm in Simulink. But with saturation block, I will get flat ...
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1answer
1k views

What is the relationship between scales and frequency in a Morlet wavelet transform?

I'm using PyWavelets, with a complex Morlet wavelet. Its complex wavelet transform function requires scales as one of its parameters, rather than frequencies. However, I don't understand the ...
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2answers
81 views

Factor $|a|^{-1/2}$ in definition of mother wavelets

The mother wavelet is defined as $$\Psi_{a,\tau}(t) = \lvert a\rvert^{-1/2}\Psi\left(\frac{t-\tau}{a}\right)\tag{1}$$ in which the factor $$ \lvert a\rvert^{-1/2}\tag{2}$$ is supposed to serve ...
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1answer
486 views

How do scaling of the coefficients for the poles of a biquad filter affect the gain?

Given a digital filter consisting of a chain of digital biquad filters. Given a digital biquad filter with a normalized Direct form 1 difference equation: $ y_n = b_0x_n + b_1x_{n-1}+b_2x_{n-2} - ...
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853 views

Scaling factor of Discrete Fourier Transform [duplicate]

I am going through DFT basics. I found somwhere it is represented by the equation $$ x[n] \ \triangleq \ \sum_{k=0}^{N-1} \ X[k] \ e^{j 2 \pi nk/N} $$ $$ X[k] \ = \ \frac{1}{N} \sum_{n=0}^{N-1} \ x[...
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1answer
53 views

Library/strategy for rotate & scale image alignment/registration

I have two raster images of maps, A and B. I know that B contains A but I do not know the scale or rotation. There should not be any other distortions between the image but there may be noise. ...
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1answer
217 views

Implementation of IIR Filter in dsPIC 33EP - Scaling

I have to implement an IIR controller in dsPIC 33EP (16-bit, fixed-point, two's complement, wrap-around, 40-bit accumulator, 32-bit multiply, 12-bit ADC) and I am using cascaded, Direct Form I second ...
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2answers
101 views

Digital RF signal vector resize algorithm

I'm searching for an algorithm for resizing a RF sampled signal in order to draw it without losing any important maximum or minimum values. The values of the vector are negative/positive around zero.