I am Professor at the University of Applied
Sciences in Karlsruhe Germany. I am interested in Signal Processing in general and especially to wavelet transformation
With MATLAB functions, the transfer function of passive networks can be determined relatively easily. The method is explained using the example of a passive low-pass filter of the sixth order, which is shown in Fig.1
Fig.1 Passive low-pass filter of the sixth order
If one tried, as would be logical, to calculate the transfer function starting from the input, it would be quite complicated. On the other hand, if you start from the output, the determination of this function is simple...
It is known [1], [3] that bandpass signals can be sampled with a sampling frequency which is lower than the sampling frequency according to the sampling theorem.
Fig. 1 shows an example of how the spectrum of a bandpass signal sampled with $f_s$ (Fig. 1a) arises in the baseband with $−f_s / 2 ≤ f < f_s/2$. The bandpass signal is assumed to have a center frequency $f_c = (f_{max} + f_{min})/2$ and bandwidth $\Delta f...
The article “Understanding the ‘Phasing Method’ of Single Sideband Demodulation” by Richard Lyons is a very good description of this topic. The block representation from the figures are clear and easy to understand. They are predestined for a simulation in Simulink. The simulation can help...
The correct answer to the @apolin quiz can be easily explained using the following Simulink model:
In MATLAB you have to initialize the two filters:
h = dftmtx (8);
h1 = h (3, :); % The filter of the quiz
h2 = h (7, :); % The mirrored filter
The impulse responses of the filters h1, h2 are complex and the responses to a broadband random signal are also complex. The two spectrum analyzer blocks then show the PSD, typical for analytical...
Hi,The amount of 0.999 of the poles causes the poles to be very close to the unit circle in the z complex plane. In implementation, the poles can go outside the...
Hello,I have created a simulink model that can be used to answer your questions very easily and clearly.A complex signal corresponding to QPSK is formed from two...
Himy opinion is that decimation cannot work here. If you want to get the analog signal from 65MHz down to 2MHz in baseband, then you may simply need to sample the...
HiI have expanded my program with the following MATLAB lines and the amplitude spectrum only shows one pick.s = [x1 x2];S = fft(s)/(2*1001);figure(3);clf;plot(0:2001,...
Hi,I did not receive your problem with these few MATLAB lines:% Script test_1.mx1 = sin(2*pi*100*(0:1000)/1000);phi = pi/3;x2 = sin(2*pi*100*(0:1000)/1000 + phi);figure(1);...
HiI think I found the bug. The option 'centered' in the command pwelch has to be replaced with 'twosided'. This gives the correct symmetry of the psd, which results...
Hi,The sketch shows how the spectra of the signals change through the filtering and downsample.In the illustration a) the original spectrum is shown. It contains...
After watching the very good blog 'Phasing Method of Single Sideband Demodulation' authorRick Lyons, I decided to simulate some of the arrangements shown (such as...
In my opinion, the formula you use is incorrect. With ifft () you generate a time sequence that you have to multiply by the complex oscillation exp (-2j pi fc t)....
Hello,Attached is a PDF file with a text in German and a translation in English. I hope it helps to understand how to describe a DC motor.RegardsDC_motor.pdf
HelloYou can subsample so that your bandpass signal is shifted in the baseband. In a Simulink model (undersample_100.slx) a sine signal of 100.01 MHz is shifted...
Hello,the following MATLAB-Script might help you:%################################################% Script sampled_mag_1.m, in which the impulse response of % a...
Hi,i think you have a time aliasing due to the sampling of the DTFT and therefore the reconstructed signal via the inverse DTFT is not the expected signal.With the...
Hello,with the following pictureI will try to answer you. For a channel with a sampling frequency of 5.4 GHz, a bandwidth of BW = 2.7 GHz in the vicinity of 8 GHz...
Hello Mr. Fragavetti,here is a MATLAB script that I used to edit an audio file. You need to change the script for your needs.Always look at the time signals. Instead...
Here is a Simulink model that can be used to answer your question.Random numbers between -1 and +1 with a period of 1/100 s are generated from a Random Number block....
Hello,I tried to analyze your wav file with a wavelet transform. With two stages, the approximation coefficients are freed from interference, giving the pitch frequency...
Hello,the idea of djmaguire is very good. For the frequency of 1700.5 HZ you have to increase the resolution of the FFT to 0.5 Hz / Bin, so you need a data block...
Hello,You can determine the autocorrelation of the excitation and the cross correlation input / output for each data block. You can then average these and improve...
I changed figure(3):figure(3);subplot(211), plot(tk, real(yk));title('Continuous signal'), grid on;subplot(212), plot(tk, y_rec);title('The samples and with sinc-functions...
To be sure that the samples are correct one has to reconstruct the continuous signal with the sinc function from these samples:function mist1N = 64; %number of samplest_vec...
Hello,Here's another solution with a block Delay Line:polyphase_solution_2.slxpolyphase_solution2.mThe delay block with a delay equal to one is necessary because...
