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# Tag Info

## Hot answers tagged frequency-domain

Accepted

### Why is the convolution of two sine waves a sinc function?

You are not convolving two sine waves, you are convolving two short snippets of sine waves. A snippet of a sine wave is the same as a real (infinite) sine wave multiplied with a rectangular window. ...
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### What is the maximum possible frequency of human voice/speech(That can be generated through human vocal cords)?

Especially What is the maximum value of frequency that human speech can have? This depends on how exactly you define it. Fricatives ("s","f","sh" ...) and plosives (&...
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### What is the maximum possible frequency of human voice/speech(That can be generated through human vocal cords)?

The fundamental speaking frequency of humans can reach up to around 1kHz, although higher values than, say, 500Hz usually appear only while singing. The harmonics and non-tonal parts of speech can ...
• 2,368
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### Convolution Theorem using DCT

I did it for the DCT-I and DCT-II. At first I thought it is about circular convolution, but it is not. After desperate attempts to do it by myself I found the article: Convolution Using Discrete Sine ...
• 366
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### Why do we calculate the second half of frequencies in DFT?

First, there's some pedantics to get out of the way: it's not FFT or DFT -- the FFT is just a specific method of computing the DFT that's advantageous under many circumstances. Any DFT takes $N$ ...
• 12.8k
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### Why does interpolation with zeros introduce frequency artifacts?

First of all, you should (re-)read the corresponding chapter(s) in your textbook or lecture notes. Understanding these basic properties of discrete-time signals is essential. Second, what you see is ...
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### Frequency Domain Filtering

This is just "faking" the magnitude response of an IIR filter. The output's magnitude spectrum looks just like it has been filtered by the IIR filter with the given frequency response. Although it may ...
• 4,295
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### What is the frequency representation of nonuniform sampling?

You might be interested in this particular reference paper: Digital Spectra Of Non-Uniformly Sampled Signals : Theories and Applications is a somewhat obscure reference (from 1988! can't go wrong!) ...
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### Discontinuities in the FFT

Your parameters aren't correct for producing a whole number of cycles for each component. For each $i$ the value of $\frac{\omega_{i}}{\omega_{s}} N$ has to be a multiple of $2 \pi$. Hope this ...
• 7,560
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### Why do frequencies of analog signals range from $-\infty$ to $\infty$ while frequencies of digital signals are restricted to $[0,2\pi]$?

The digital frequency span of 0 to $2\pi$ is the normalized angular frequency given in units of radians per sample. For example, if we had a frequency tone that went $0.2\pi$ radians/sample, then it ...
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Accepted

### Absolute value based AM envelope detection viewed in the frequency domain

$\DeclareMathOperator{\sgn}{sgn}$ The modulating signal in AM is $$s(t) = C + a(t)\text,$$ where $a(t)$ is the (audio) amplitude, and $C$ is a constant so that $s(t) \ge 0 \;\forall t$. (Otherwise, ...
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### What is the Effect of Multiplying a Function by the Unit Impulse Function in the Frequency Domain?

I think there is a slight typo in Robert Bristow-Johnson's answer. Should be \begin{align} x(t) &= \frac{1}{2 \pi} \int\limits_{-\infty}^{\infty} X(\omega) e^{j \omega t} \, \mathrm{d}\omega\\ \\ ...

### Proof of fourier transformation of multiplication of two signals

I am very thankful to Dilip-sarwate and Gilles, who took their precious time to understand my problem and guide me. So, Now I'm going to write the correct solution to my question. Which is as follows: ...

### If a square wave is a sum of odd harmonic impulses, why is it continuous in the frequency domain?

A square wave is not a Sinc function in the frequency domain, but a sampled Sinc function (Even as a continuous function, the non-zero values are samples of the Sinc function in frequency). An ...
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### Relation of zero-padding and frequency resolution

why do I get "better" frequency resolution in case of adding zero-padding to this signal. You do and you don't. Zero padding increases resolution by interpolating between existing data ...
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We usually talk of $j\omega$ when we're also interested in the Laplace transform of a signal / system, but want to just talk about the frequency response. The physical meaning of the imaginary part ...