Spektrá
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Spektrá
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %
% %
% Takto sa kresli spektrum signalu typu Sinus s f 440 Hz. %
% %
% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %
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
