# Questions tagged [frequency]

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

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### Angle modulation spectrum

Is angle modulation spectrum always discrete or this property only holds for periodic modulating signal?
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### Choices of convention and notation for the Fourier transform?

The definitions of the Fourier transform and inverse Fourier transform I learned in college were $$F(j\omega) = \int_{-\infty}^{\infty} f(t) e^{-j\omega t}\ dt$$  f(t)=\frac{1}{2\pi}\int_{-\...
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### 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?
531 views

### Weird results out of fourier transform of unknown signal, what am I doing wrong?

It has been a long time since I studied engineering, please forgive my mistakes. I got data sampled from a digital accelerometer. It is sampled at 20 hz, then collapsed into 1 second epochs. The data ...
71k views

### 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 ...
1k views

### What mathematical model of audio can make possible pitch shifting of individual notes in (timbrally complex) polyphony?

My question is: What mathematical model of polyphonic sound can make possible the changing (i.e. pitch shifting) of individual musical notes in a multi-voice-in-single-channel audio recording of a ...
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### Finding the input bit rate of an analogue input

Suppose I have 4 of 300bps synchronous digital input and 1 of analogue input with a bandwidth of 500Hz. The analogue input is sampled at 4bit using PCM. All the channels are multiplexed with TDM. As ...
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 ...