# Questions tagged [frequency]

Frequency in signal processing is the number of cycles (of the signal) per second.

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

This has been one of the holes in my cheddar cheese block of understanding DSP, so what is the physical interpretation of having a negative frequency? If you have a physical tone at some frequency ...
176k views

### What is meant by a system's “impulse response” and “frequency response?”

Can anyone state the difference between frequency response and impulse response in simple English?
4k views

### Which time-frequency coefficients does the Wavelet transform compute?

The Fast Fourier Transform takes $\mathcal O(N \log N)$ operations, while the Fast Wavelet Transform takes $\mathcal O(N)$. But what, specifically, does the FWT compute? Although they are often ...
11k views

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### How to find period/envelope that is larger than sample size?

Mercury's distance from the solar system's barycenter (in kilometers) can be approximated as: ...
3k views

### Upsample data using FFTs. How is this exactly done?

I am basing my question on this post here, because I would like additional details on it, as I have not had any success in re-creating it. I would like to simply learn, in no uncertain terms, how to ...
698 views

### Separating waves of very close wavelengths

I'm new to wave problems, so excuse my simplified words. I have a signal consists of high range of frequencies . I applied a Band-pass filter to this signal and I have been able to separate it to ...
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### FFT for a single frequency

I was looking for a more efficient way of finding the magnitude and phase of a signal at a certain frequency without performing an FFT because it produces more information than I need and I came ...
494 views

### Comb-like peaks in frequency spectrum

I am currently working on a project which involves measuring the sound produced by the onset of a vapour bubble in boiling water. All the experiments went perfectly well and I'm now trying to obtain a ...
4k views

### Sampling frequency of modulated signal

A very naive question... A signal with bandwidth of 20 MHz is modulated using a carrier of 1 GHz. What will be the sampling frequency? I was asked this question during an interview. I answered 2 GHz ...
381 views

### Sampling bandpass signal with spectral replications

I want to clear my thinking on how to approach problems of the type characterized below. I guess what we want to do is select a sample rate of a sufficient size such that this signal can be fully ...
11k views

### FFT Zero Padding - Amplitude Change

I'm just learning about Fourier Transforms and as an input I'm using a WAV file (Matlab) and taking one channel of it and performing a quick Fourier transform. I've zero padded the input, as I've been ...
When talking about general periodic continuous-time signals for which $$x(t + T_0) = x(t)$$ where $T_0$ is the fundamental period we define the fundamental frequency $\omega_0$ as $\omega_0 = 2\pi/T_0$...