# Questions tagged [frequency]

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

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### 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 ...
1answer
436 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 ...
2answers
1k views

### Am i performing Sinesweep correctly?

I am bit unsure whether i am doing i sine sweep correctly. I am feeding my system a sine wave with f hertz within a given time interval and log its output. And then i do the same for another ...
4answers
232 views

### Very basic question about how we define frequency in signal processing

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 $\omega_0 = 2\pi/T_0$...
2answers
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### FFT resolution and sampling frequency

I am computing FFT of the data which I am receiving from an ADC with SPI protocol. Since resolution of FFT is related to $F_s/N$ where $N$ is the FFT length and $F_s$ is the sampling frequency of ADC, ...
1answer
190 views

### Can I run a GA to optimize wavelet transform?

I am running a wavelet transform (cmor) to estimate damping and frequencies that exists in a signal.cmor has 2 parameters that I can change them to get more accurate results. center frequency(Fc) and ...
1answer
2k views

### Calculate average mean FFT Magnitude in bins [duplicate]

I am analyzing sounds of daily activities recorded by a smartphone. For example walking, getting up from bed, falling, running etc.. (one at the time). Let’s take one them. My goal is to convert from ...
1answer
120 views

### Matlab produces two unknown spikes in custom FFT

I'm making a relatively small Cooley–Tukey FFT in Matlab and I'm noticing unusual spikes in the result compared with Matlab's own FFT. The figure below shows the signal flow of my program. It's a ...
1answer
211 views

### Pilot tone frequency doubling

U.S. Broadcast FM stereo includes a $19\textrm{ kHz}$ pilot tone that needs to be frequency doubled to help demodulate the DSB stereo difference signal. How can this frequency doubling be done ...
2answers
228 views

### What are the implications of resampling the derivative of a signal with a higher frequency than the original signal?

Suppose I have a digital signal measured with sampling time, $T_s=1$ sec. If I take it's derivative, it will, naturally have $T_s=1$ sec. But what are the implications if I re-sample this derivative ...
1answer
590 views

### Regarding phase and frequency components in the signal [closed]

As I am not a signal processing student, I have limited understanding of the concepts. The general formula for sine wave is $$s(t)= A \sin(\omega t-p)$$ where $A$ is amplitude $\omega$ is ...
3answers
821 views

### Distribution of energy in frequency bands

On my wav-file (music), I do a short-time Fourier transform (STFT). I have spectrum, which spans from $0\textrm{ Hz}$ to $f_s/2$. I took out the range between $1$ and $1000\textrm{ Hz}$, which I ...
0answers
113 views

### Estimating frequency when there's little isolation between signal and noise frequencies

Say I have a signal which is guaranteed to have a frequency between 110-120 Hz but is corrupted by interference signals that're very close to this frequency range. For example, let the interference ...
1answer
1k views

### Correlation between Sin and Square wave

I would like to know how $\frac T2$ came for time period in the image below.Because I think the frequncy is 1 so time period should be 1.Is that correct? or can anyone help me.. The article from ...
1answer
90 views

### Correlation between frequency and initial phase estimates using FFT

Why is there a high negative correlation between frequency estimation errors and initial phase estimation errors when measured using FFT? I have a simple code showing this negative correlation. is ...
3answers
6k views

### Calculating maximum signal frequency knowing its sampling rate?

I was curious as to how I could calculate the maximum frequency of a signal knowing only its sampling rate (for example 125 nanoseconds). Does the sampling theorem have anything to do with it (...