## Re: changing FFT resolution of known sweep signal leads to unexplained spectrum

May be the imput signal is the key - here is a spectrogram of the signal    load test_data_3569.txt    x = complex(test_data_3569(:,1), test_data_3569(:,2)); ...

## Re: changing FFT resolution of known sweep signal leads to unexplained spectrum

It looks like only this part of the spectrum is preserved in the first part of the signal:    plot(abs(fftshift(fft(x(1:8000), 15000))));    hold on    plot(abs(fftshift(fft(x(8000:end),...

## Re: PSD estimation when I have oversampled data

The Welch method is not the same as downsampling and averaging. Welch will keep the bandwidth and increase the width of the frequency bins. Downsampling and averaging...

## Re: Matrix arithmetic in DSP (specifically with regards to convolution / deconvolution)

Signals:u = [u1, u2, u3, u4]v = [v1, v2, v3]u can be represented as a matrixA = [u1, 0, 0 u2, u1, 0u3, u2, u1u4, u3, u20, u4, u30, 0, u4]Sou * v = A v

## Re: Has the LinkedIn.com Web Site Been Scanning Through Your Computer's E-Mail Files Without Your Permission?

LinkedIn is owned by Microsoft but I don't think they are scanning third party emails. Any other connections?

## Re: Reverberation rejection filter

Yes, the matched filter should be modified. The same way you are filtering the signal you need to filter the waveform used to create the matched filter. May be...

## Re: Reverberation rejection filter

Have you modified the matched filter also?

## Re: Verification of range resolution using simulations

Hi Naumankalia,To produce a delayed chirp (with whatever delay you want) you need to:Delay the chirp, e g. instead of  chirp(t, f0, T, f1)   you need  chirp(t...

## Re: Verification of range resolution using simulations

Hi,Is the question about how to produce two delayed chirps or how to matched filter them or how to decide if the second chirp can be resolved?At small delays the...

## Re: How to calculate time delay estimation?

Normally cross-correlation (matched filter) is enough to get the delays: cx = xcorr(x_rx, x_tx); cx = cx(length(x_rx):end); plot(db(cx)),  ymax = max(db(cx)),  ylim([ymax-40,...

## Re: 3D fft Matlab

In Matlab you have build in function for N-D FFT. The algorithm for the 2-D case is also described in Ch24 of The Scientist and Engineer's Guide to Digital Signal...

## Re: Window-presum FFT problem

Thanks Dr. mike for the intuitive explanation. Still it should work if the signal is split into more than 4 blocks in which case the combination will not look so...

## Re: Window-presum FFT problem

But there are no shifted sinks - just a single sinc that multiplies the whole sequence before chopping. Now I see that it will modify the spectrum of the signal...

## Re: Window-presum FFT problem

Thanks for the link Steve. Krasin

## Re: Window-presum FFT problem

Hi Lyons! In which section of your DSP book, chapter 13, I can find more information about WOLA? I can't discover such abbreviation there. The algorithm described...

## Re: Coherent Sampling (Very Brief and Simple)

Why M and N should be mutually prime? I can see some explanation in chipmuenk post but I still can't get it.

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