Javoblar Kotelnikov teoremasi

# change plot viye
ax = plt.gca()
ax.spines[’right’].set_color(’none’
ax.spines[’top’].set_color(’none’)
ax.spines[’bottom’].set_position((’data’,0))
plt.tight_layout()

Kvantlash va namuna olish qadamlari noto‘g‘ri tanlansa, signalni analogdan diskret shaklga o‘tkazish buzilish bilan sodir bo‘ladi. Namuna olish qadami va kvantlash qadami noto‘g‘ri tanlanishga misol ko‘rib o‘tamiz.

Sinus grafigini o‘rnatish. Signa uzunligi n = 64 namunalar bo‘lib, unga garmonik signalning bir davri qo‘yiladi. Kvantlash qadami shunday belgilansinki, bizda d = 3, 5, 8, va 32 ta qiymatlar bo‘lsin.
# time vector
t = np.linspacye(0, 1, n, endpoint=Truye)
# sine wave
ds = np.sin(2*np.pi*t
# discrete step
step_lst = np.array([3, 5, 8, 32])
#plot figure
fig = plt.figure(figsize=(12, 6), dpi=80)
for i in range(4):
tt = np.linspacye(0, 1, step_lst[i], endpoint=Truye)
plt.subplot(2, 2, i+1)
plt.title(Nuqtalar soni = {}’.format(step_lst[i]))
plt.plot(t, ds, ’-’, linewidth=2.0)
plt.plot(tt, np.sin(2*np.pi*tt), ’--o‘, linewidth=1.5, markersize=8)
plt.step(tt, np.sin(2*np.pi*tt), linewidth=1.5)
plt.grid()
plt.xlim([0, 1])
plt.tight_layout()


Diskretlash jarayonini Matlab dasturida qo‘yidagicha keltirish mumkin.
clear all;
close all;
clc;
%f=input(’Chastotani kiriting‘);
f=5;
%fs=input(’Diskretlash chastotasini kiriting‘);
fs=50;% Diskretlash chastotasi 50 hz
ts=1/50;
t=0:ts:1;% 50 ta diskret namuna
x1=sin(2*pi*f*t);% bu yerda f kiruvchi signal chastotasi
subplot(3,1,1);
plot(t,x1);
hold on;
plot(t,x1,’*’);
ylabel(’amplitude’);
xlabel(’title’);
title(’Diskretlash chastotasi 50 hz signal1’);
% Diskretlash chastotasi 25 hz
fs1=25;
ts1=1/25;
t1=0:ts1:1;
x2=sin(2*pi*f*t1);
subplot(3,1,2);
plot(t1,x2);
hold on;
plot(t1,x2,’*’);
ylabel(’amplitude’);
xlabel(’title’);
title(’Diskretlash chastotasi 25 hz signal1’);
% Diskretlash chastotasi 12.5 hz
fs2=12.5;
ts2=1/12.5;
t2=0:ts2:1;
x3=sin(2*pi*f*t2);
subplot(3,1,3);
plot(t2,x3);
hold on;
plot(t2,x3,’*’);
ylabel(’amplitude’);
xlabel(’title’);
title(’Diskretlash chastotasi 12.5 hz signal1’);


Salimov Husniddin 214-18