Rank: 34 based on 1262 downloads (last 30 days) and 19 files submitted
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Hristo Zhivomirov

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Company/University
Techical University - Varna

Personal Profile:

Hristo Zhivomirov was born in Varna, Bulgaria, in 1987. He received his B.Sc. and M.Sc. degrees in Communication Equipment and Technologies from Technical University of Varna, Bulgaria in 2010 and 2012, respectively. He is currently an Assist. Professor in department of Theory of Electrical Engineering and Measurement and a Ph.D. student in department of Communication Equipment and Technologies, Technical University of Varna. Mr. Zhivomirov is a member of IEEE, USB Bulgaria and FSTU Bulgaria. His research interests include the field of signal processing, circuits and systems, as well as audio and low-voltage measurements.


 

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Files Posted by Hristo Zhivomirov View all
Updated   File Tags Downloads
(last 30 days)
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02 Dec 2014 Screenshot Arbitrary Spectral Slope Noise Generation with Matlab Implementation Arbitrary spectral slope ( f^alpha) noise generation via spectral processing of white noise. Author: Hristo Zhivomirov noise, measurement, signal processing 25 0
02 Dec 2014 Screenshot Pink, Red, Blue and Violet Noise Generation with Matlab Implementation Pink, red, blue and violet noise generation via spectral processing of white noise. Author: Hristo Zhivomirov noise, measurement, signal processing 144 0
02 Dec 2014 Screenshot Generation of Audio Test Signals with Matlab Implementation Generation of sine wave, square wave, chirp, sinc, white and pink noise via sound card. Author: Hristo Zhivomirov measurement, signal processing 38 0
  • 5.0
5.0 | 1 rating
02 Dec 2014 Screenshot Phase Difference Measurement with Matlab Implementation Phase difference measurement between two signals via spectral analysis. Author: Hristo Zhivomirov measurement, signal processing 62 0
05 Oct 2014 Screenshot Noise Measurement with Matlab Implementation Estimation of the Noise ASD, Noise PSD and Noise Voltage referred to the output of a circuit. Author: Hristo Zhivomirov measurement, signal processing 40 1
  • 5.0
5.0 | 1 rating
Comments and Ratings by Hristo Zhivomirov View all
Updated File Comments Rating
28 Sep 2014 Sound analysis with Matlab Implementation Time and frequency analysis, measurement of the crest factor, the dynamic range, etc. Author: Hristo Zhivomirov

Hi, Nguyen! The basic reason for a minus sign in front of some dB value is because the logarithm of a number 0<x<1 is negative.

13 Jul 2014 PSD (Power Spectral Density), and Amplitude Spectrum with adjusted FFT FFT computes PSD and one sided amplitude spectrum Y[f] of 1d signal Author: Youssef KHMOU

Youssef, if you want to obtain the power spectral density PSD (W/Hz) you should divide the power spectrum Power to equivalent noise bandwidth ENBW of the window.

S1 = sum(win);
S2 = sum(win.^2);
ENBW = Fs*S2/(S1^2);
PSD = Power/ENBW;

In your case there is no window (or there is rectangular one), so ENBW = Fs/L.

25 Feb 2014 Inverse Short-Time Fourier Transformation (ISTFT) with Matlab Implementation Time-Frequency resynthesis via Inverse Short-Time Fourier Transformation (ISTFT) Author: Hristo Zhivomirov

Hi Yousef,

First of all thank you for the comment and for your interest in my submission.
Now here is the answer:

1) choose h = wlen/(4*n), where n = 1, 2, 3, ... (h = wlen/2 does not meet OLA-constraint, check with WindowChoice.m).
2) choose nfft = wlen (nfft > wlen cause interpolation in the time domain of every signal segment = errors in resynthesis, so if you really want interpolation you must use zero-padding technique in time-frequency domain).

Try this:

clear, clc, close all

% define signal parameters
% sine-wave signal (stationary signal)

fs = 48000;
t = 0:1/fs:1-1/fs;
x = 10*sin(2*pi*t*10);

% define analysis and synthesis parameters
wlen = 64;
h = wlen/4;
nfft = wlen;

% perform analysis and resynthesis
[stft, f, t_stft] = stft(x, wlen, h, nfft, fs);
[x_istft, t_istft] = istft(stft, h, nfft, fs);

% plot the original signal
figure(1)
plot(t, x, 'b')
grid on
axis([0 1 -15 15])
set(gca, 'FontName', 'Times New Roman', 'FontSize', 14)
xlabel('Time, s')
ylabel('Amplitude, V')
title('Original and reconstructed signal')

% plot the resynthesized signal
hold on
plot(t_istft, x_istft, '-.r')
legend('Original signal', 'Reconstructed signal')

Best Regards,

Hristo Zhivomirov

30 Aug 2013 PSD (Power Spectral Density), and Amplitude Spectrum with adjusted FFT FFT computes PSD and one sided amplitude spectrum Y[f] of 1d signal Author: Youssef KHMOU

Figure 2 (Power Spectral Density, logarithmic scale) is not correct. The Y scale does not represent the PSD magnitude in dB. It is just the same PSD like Figure 1, but represented on logarithmic Y scale. If you want to have a PSD in dB, use PowerdB = 10*log10(Power) and plot(f, PowerdB).

Comments and Ratings on Hristo Zhivomirov's Files View all
Updated File Comment by Comments Rating
28 Sep 2014 Sound analysis with Matlab Implementation Time and frequency analysis, measurement of the crest factor, the dynamic range, etc. Author: Hristo Zhivomirov Hristo Zhivomirov

Hi, Nguyen! The basic reason for a minus sign in front of some dB value is because the logarithm of a number 0<x<1 is negative.

26 Sep 2014 Sound analysis with Matlab Implementation Time and frequency analysis, measurement of the crest factor, the dynamic range, etc. Author: Hristo Zhivomirov Nguyen Thanh Phong

Why dB have "-"?

19 Sep 2014 Sound analysis with Matlab Implementation Time and frequency analysis, measurement of the crest factor, the dynamic range, etc. Author: Hristo Zhivomirov Nguyen Thanh Phong

Thank you very much!

18 Sep 2014 Short-Time Fourier Transformation (STFT) with Matlab Implementation Time-Frequency analysis via Short-Time Fourier Transformation (STFT) Author: Hristo Zhivomirov Michael Schwartz

Thank you. Very straight forward and easy to understand. Exactly what I needed. Thanks!

18 Aug 2014 Short-Time Fourier Transformation (STFT) with Matlab Implementation Time-Frequency analysis via Short-Time Fourier Transformation (STFT) Author: Hristo Zhivomirov jim

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