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

The correct answer to the quiz of @apolin

Josef Hoffmann January 10, 2020

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...


Re: DF2T IIR SOS

Reply posted 2 months ago (04/05/2020)
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...

Re: Simplifications With Eulers Equation (DTFT, DTFS)

Reply posted 3 months ago (02/12/2020)
Euler_2.pdf

Re: Simplifications With Eulers Equation (DTFT, DTFS)

Reply posted 3 months ago (02/12/2020)
I send you the file Euler_1.png

Re: Simplifications With Eulers Equation (DTFT, DTFS)

Reply posted 3 months ago (02/12/2020)
Hi there,you have to find a suitable factor so that you can always use the Euler formula, e.g. here:Euler_1.png

Re: ADC sampling rate matlab/simulink M-PSK

Reply posted 5 months ago (12/30/2019)
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....

Re: Extract pitch of irregular signal ?

Reply posted 7 months ago (11/03/2019)
The plot is only a section at the beginning of the FFT !

Re: Extract pitch of irregular signal ?

Reply posted 7 months ago (11/03/2019)
The second frequency is just the reflection of the first frequency in the second Nyquist interval !

Re: Extract pitch of irregular signal ?

Reply posted 7 months ago (11/02/2019)
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...

Re: FFT Channelizer and PFB

Reply posted 8 months ago (10/08/2019)
Please try to use the FFT for analysis and synthesis or for both the iFFT. I use this in my textbook and it works.

Re: Average Impulse Response from multiple measurements

Reply posted 10 months ago (08/12/2019)
An example of such identification:% Skript identif_2.m, clear;% ------ SignalsN = 1024;%x = sign(randn(1,N));x = randn(1,N);% Systemnord = 64;h = fir1(nord, 0.2); ...

Re: Average Impulse Response from multiple measurements

Reply posted 10 months ago (08/12/2019)
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...
try this !!!N = 64; %number of samplest_vec =(0:1/N:1-(1/N)); % time valuestk = (0:1/512:1-1/512); % continuos timeA3=1;f3=30; % signal frequencyy = (A3*exp(j*2*pi*f3*t_vec));yk...
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...

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