Linked Questions

8
votes
3answers
1k views

Spectral Leakage in layman's terms

I'm trying to understand the concept of spectral leakage for the DFT, without going deep to the mathematical intricacies (it's for practical purposes). I've read from the book "Introduction to Digital ...
1
vote
3answers
3k views

FFT of any sinusoidal signal -- how many point fft to take?

suppose I have to measure the DFT of an 60 hz sinusoidal signal and calculate upto 20 harmonics of this. Value of the 20th harmonic will be 20*60 = 1200 HZ. Then my sampling frequency should be >= 20*...
3
votes
1answer
1k views

For 2D signals can it be said that the frequency response is the same as the Fourier transform?

Say I have a signal: [1, 1 , 1; 1 100 1; 1 1 1];, I wanted its frequency response, then can I take its FFT? Why does MATLAB have two functions to do the same ...
1
vote
2answers
3k views

Difference between bandpass filter and using fast fourier transform to extract power of frequency bands

In signal processing, I have heard of two terms: Using band-pass filter to extract some frequency bands. Using Discrete/Fast Fourier Transform (DFT/FFT) to extract some frequency bands. Are these ...
1
vote
2answers
1k views

Different way to separate a particular frequency from a signal

Let's say I have a signal which is composed of 2Hz,10Hz,17Hz,19Hz and 25Hz discrete time sinusoidal waves and I need to allow only 17Hz component to pass. As far as I know, the standard way to ...
0
votes
1answer
716 views

Upsampling and comb function

Could somebody explain how upsampling works with comb function. How comb function looks for upsampling process? (if it possible I would appreciate if answer would be related to DFT)
1
vote
2answers
915 views

Find the Equivalent Noise Bandwidth

I have already asked (in another thread) how to quantify (specify) the window function I have created. One figure I need it seems is the Equivalent Noise Bandwidth (ENBW) Or Noise Equivalent Bandwidth....
-1
votes
1answer
584 views

Digital signal and frequency analysis

I am generating a digital signal with software. I have defined the vector $$[0,1,1,1,0,1,0,1,0,1,0,0,0,0,0,0,0,0,0,0] $$ and my sampling rate is 8 million per second. The frequency spectrum is ...
-1
votes
1answer
410 views

Finding frequency of data given in time domain

Think there is an analog signal source and we are recording it with a data logger. Sampling rate isn't important in here. We know the analog signal is 0 mV when time 0 and goes to 1000mV in 1000 ...
1
vote
3answers
199 views

spectral leakage for integral number of periods

I'm attempting to understand spectral leakage and read the following quote on wikipedia: Windowing a sinusoid causes spectral leakage, even if the sinusoid has an integer number of cycles within a ...
1
vote
2answers
139 views

Estimate Parameters of Linear Combination of Harmonic Signals with Partial Known Frequencies

Consider real signal of the form: $$ \begin{align*} x(n) = &\sum_{m=1}^{M} \left( c_m \cos(2\pi f_m n) + s_m \sin(2\pi f_m n) \right) =\\ &\sum_{m=1}^{M} a_m \cos(2\pi f_m n + \phi_m) \end{...
1
vote
1answer
144 views

Summation of audio tone

Suppose you transmit at a single tone $\omega\textrm{ rad/sec}$ and you have two receiving microphones $i=1,2$ which sample at $r$ samples per second. Assume you have a direct path with coefficients $...
1
vote
1answer
57 views

misunderstanding of spectral leakage

I want to understand spectral leakage. I understand that whenever we feed $N$ time-samples of a periodic, continuous, signal into a FFT algorithm we are multiplying in time-domain the true periodic, ...