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2 votes

Why doesnt DFT Padding cause sinc like features

lots of good stuff in the above answer. But you can absolutely see the sinc function in the frequency domain - just pick a sin wave that's got a period that evenly divides the new signal length. For ...
njudell's user avatar
  • 21
4 votes

Why doesnt DFT Padding cause sinc like features

@George kirby. I suggest you discard that notion of "multiplying a step function on top of the original signal to form a longer time sequence". I believe such a multiplication is not ...
Richard Lyons's user avatar
9 votes
Accepted

Why doesnt DFT Padding cause sinc like features

The OP is showing very good insight in all the comments stated. A product in the time domain with a rectangular pulse is convolution in the frequency domain with a Sinc. In fact zero padding in time ...
Dan Boschen's user avatar
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0 votes

Jitter model does not behave as expected after FFT

Alright, pass two. I'm changing all of the notation from continuous time ($s(t)$, $\phi(t)$) to discrete time. After all, this is a sampled signal going into an FFT. If $\phi[n]$ is small in ...
robert bristow-johnson's user avatar
0 votes

Jitter model does not behave as expected after FFT

By adding small angle white noise to the phase term, the OP is correctly modeling "White Phase Noise" which would result in the flat spectrum shown. As a general note, phase noise is ...
Dan Boschen's user avatar
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1 vote
Accepted

Trying to replicate results from tfestimate function in Matlab

I can confirm the following algorithm successfully replicates the tfestimate function for my signals $x(n)$ and $y(n)$, Algorithm Divide $x(k)$ and $y(k)$, where $k=0,1,\ldots,N-1$, into data ...
wolfiesax's user avatar
1 vote
Accepted

What function can be used to describe periodicity of the signal

You are sampling, then resampling, then (essentially) filtering. Everything that you see can be explained because of the combination of these effects. You're starting with a signal at 100Hz: $x(t) = \...
TimWescott's user avatar
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0 votes

Why i am not getting same convolution plots?

What you need to do is pad the signals properly. By padding you'll be able to extract the inner part of the circular convolution applied by the frequency domain multiplication. You may have a look at ...
Royi's user avatar
  • 19.6k
0 votes
Accepted

instantaneous frequency for a complex signal

This line [f]=instfreq(lfm); should be [f]=instfreq(lfm)*fs; If I do that and plot the true $\phi$ and the estimated $\phi$ ...
1 vote

Calculating stopband cut-off frequency and stopband attenuation for FIR lowpass window filter

Some helpful advice: The order of 5 for an FIR filter is very small. I assume from the OP's comment that the exercise will be to compare FIR and IIR filters for very small order. Plotting the spectrum ...
Dan Boschen's user avatar
  • 51.4k
0 votes
Accepted

Why is my Hard Decision Decoding of Convolutional codes not performing well?

Are you accounting for quantization noise in your calculation of the bound when decoding with HDD? One-bit representation is a special case anyway, but the quantization noise has an impact, generally. ...
vml's user avatar
  • 16

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