# Tag Info

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### Does the Nyquist frequency of the cochlear nerve impose the fundamental limit on human hearing?

Does the Nyquist frequency of the Cochlear nerve impose the fundamental limit on human hearing? No. A quick run-through the human auditory system: The outer ear (pinnae, ear canal), spatially "...

### A question about sampling rate of cosine signal

It is actually not distorted, it is sampled at high enough rate. What fools you is the straight lines drawn between sample points, it gives you a false impression of the waveform. It shows you a ...

### What is the difference between phase noise and frequency noise?

Phase Noise and Frequency Noise are not two different noise sources, they are artifacts of the same noise, it is just a matter of what units you want to use. Frequency and Phase are directly related ...
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### Amplitude modulation vs sampling rate?

The OP's opening statement is incorrect: $f_s > f_{max}/2$ prevents frequency aliasing for a bandlimited signal, but not amplitude aliasing $f_s > 2 f_{max}$ prevents aliasing. It's as simple ...

### 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 ...

### 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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### 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 $N$ ...

### Doppler shift in time domain?

The term Doppler Shift is actually a bit of a misnomer. The frequencies are not actually shifted but they are scaled (see http://fourier.eng.hmc.edu/e101/lectures/handout3/node2.html for definition of ...

### A question about sampling rate of cosine signal

The actual requirement is to sample at GREATER then twice the bandwidth, not at a rate equal to it... So only your 80Hz same set actually meets the requirement, because the 60Hz case is ambiguous in ...
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### How can I determine the frequency of a sine wave signal with gradually increasing frequency?

Instantaneous frequency is the time derivative of phase. Since the OP already has the analytic signal representation of the chirp, every sample can easily be used for the frequency estimate (unlike ...

### What is the physical significance of negative frequencies?

even though everything important has been said I wanted to add some code and more visual keys on why the following formulas require positve and negative frequencies to make clear that negative ...

### Estimate Sine Frequency under White Noise — simple and effective method

I assume the model to be: $$x \left[ n \right] = \sin \left[ 2 \pi \frac{f}{ {f}_{s} } n + \phi \right] + w \left[ n \right]$$ Where $w \left[ n \right]$ is white noise uncorrelated with the ...

### Is there other basis possible for DFT?

$k/N$ with $N$ bases is the only basis which is all of: Orthogonal & invertible. Means we don't lose any information. Invertibility can be seen to follow from the DFT being a square (N x N) ...
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### Does analytic signal have positive instantaneous frequency?

It is not the case that the instantaneous frequency of an analytic signal is always positive. In general, the instantaneous frequency can become negative, also for analytic signals. I'll show this ...

### Are there libraries for extraction of sound wave features?

From the ones I've been using I can recommend: YAAFE - very pleasant to work with in Python ESSENTIA - another one I like particularly due to Python integration aubio FEAPI Aquila - friend of mine ...
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### Estimate Sine Frequency under White Noise — simple and effective method

If you have a low-noise and well-sampled signal, a quick way to estimate it is to find $\sqrt{-f''(t)/f(t)}$. For a signal $$f(t)=A \sin(\omega t+\phi)$$ the second derivative is -A \omega^2 \sin(\...

### Audio frequency modulation algorithm

You need to build a time varying delay, where you can modulate the delay amount over time. The peak delay modulation is a function of your maximum desired frequency shift and the modulation ...

### A very basic question about processing high frequency signals

In digital signal processing, one almost never deals directly with high-frequency signals. The reason is that the frequency band that a signal occupies is completely irrelevant to the information that ...

### Discrete Time Signal Property

I think it means the "apparent" frequency of oscillation. It's poorly worded. What's happening is that the frequency is increased to the Nyquist rate in the first half and then above it, causing ...
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### Why is it called continuous-time frequency?

$\Omega$ is the usual angular frequency in radians per second, and is equal to $2 \pi f$. It is the way to measure frequency for continuous-time signals. In discrete-time, frequency is measured in ...

### How can I get the power of a specific frequency band after FFT?

To get the total power across bins, sum the power in each bin. Also you need to compensate for your window loss if you want an accurate result. For a rectangular window, the power in each DFT bin is ...

### A question about sampling rate of cosine signal

There is no aliasing as 𝑓 = 30 Hz is less than or equal to the folding frequency, 30 Hz and 40 Hz, respectively. Yes and no. There isn't significant aliasing when you're sampling at 80Hz, because ...
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### Calculate the magnitude and phase of a signal at a particular frequency in python

You can find the index of the desired (or the closest one) frequency in the array of resulting frequency bins using np.fft.fftfreq function, then use ...

### Estimate Sine Frequency under White Noise — simple and effective method

This depends on the precision needed. If it's a pure sine wave that's noise free, you can get a very quick estimate by measuring the difference between two zero crossings. The tricky part is that most ...

### Estimate Sine Frequency under White Noise — simple and effective method

A common way to do this is to take the FFT of the input signal. Since the frequency might not be right at a FFT bin, usually a second step of interpolation is done after choosing the initial peak. A ...