Signaly

Signály

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% Takto sa kresli spektrum signalu typu Sinus s f 440 Hz.     %                            
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   f_sample = 8000;               % [Hz] - pre telefony OK                                 
   duration =    1;               % [s]  - jedna sekunda                                   
       freq =  440;               % [Hz] - komorne A4 = 440 Hz                             
          A =  0.9;               % [V]  - amplituda signalu z <-1,1>                      
                                                                                           
       time = 0 : (1/f_sample) : duration;                                                 
SinusSignal = A * sin( 2*pi*freq*time + 0 );                                               
                                                                                           
   T_sample = 1/f_sample;                                                                  
          N = length(SinusSignal);                                                         
                                                                                           
 maxtime = (N-1) * T_sample;      % Doba trvania signalu                                   
                                                                                           
 time = (0:N-1) * T_sample;       % Casova osa                                             
 freq = (0:N-1) / maxtime;        % Kmitoctova osa                                         
                                                                                           
                                                                                           
% Fourierova analyza:                                                                      
                                                                                           
S = fft(SinusSignal);             % Vypocet komplexneho spektra                            
Mod = 2/N * abs(S);               % Spravne amplitudove spektrum                           
Pha = 180/pi * angle(S);          % Fazove spektrum v stupnoch                             
                                                                                           
N1 = round(N/2);                  % Kreslime len relevantu cast po f_sample/2              
                                                                                           
subplot(2,1,1);                                                                            
plot(freq(1:N1),Mod(1:N1));       % Aplitudova frekvencna charakteristika                  
                                                                                           
subplot(2,1,2);                                                                            
plot(freq(1:N1),Pha(1:N1));       % Fazova frekvencna charakteristika