BÁO-CÁO-THỰC-HÀNH-THÍ-NGHIỆM-XỬ-LÍ-SỐ-TÍN-HIỆU-NHÓM-1

TRNG I HC CNG NGHIP TP.HCM

KHOA CNG NGH IN T

BO THC HNH TH NGHIM X L S TN HIU

GVHD : Thy L VN HNG

NHM: 1

Nguyn Trung Dng: 12066601

Nguyn c Anh: 12010011

Nguyn Ch Cng: 12026261

Nguyn Vn Sinh: 12015781

Trn Thanh Bnh: 12009821

Chng 3

S RI RC THEO MIN THI GIAN PHN TCH FOURIER

V D 3.3 : Tnh ( ) trong v d 3.1 ti 501 im ri rc trong khong

v v li n di dng bin , gc, phn thc v phn o .

Code:

Kt Qu

w=[0:1:500]*pi/500;

X=exp(j*w)./(exp(j*w)-0.5*ones(1,501));

magX=abs(X); angX=angle(X) ; realX=real(X);imagX=imag(X);

subplot(2,2,1); plot(w/pi,magX); grid

xlabel('frequency in pi units'); ylabel('Magnitude'); title('Magnitude Part');

subplot(2,2,3); plot(w/pi,angX);grid

xlabel('frequency in pi units'); title('Angle Part'); ylabel('Radians')

subplot(2,2,2); plot(w/pi,realX); grid

xlabel('frequency in pi units'); title('Real Part'); ylabel('Real')

subplot(2,2,4); plot(w/pi,imagX); grid

xlabel('frequency in pi units'); title('Imaginary Part'); ylabel('Imaginary')

V D 3.4 :

Code:

Kt qu:

n = -1:3; x = 1:5; k = 0:500; w = (pi/500)*k;

X = x * (exp(-j*pi/500)) .^ (n'*k);

magX = abs(X); angX = angle(X);

realX = real(X); imagX = imag(X);

subplot(2,2,1); plot(k/500,magX);grid

xlabel('frequency in pi units'); title('Magnitude Part')

subplot(2,2,3); plot(k/500,angX/pi);grid

xlabel('frequency in pi units'); title('Angle Part')

subplot(2,2,2); plot(k/500,realX);grid

xlabel('frequency in pi units'); title('Real Part')

subplot(2,2,4); plot(k/500,imagX);grid

xlabel('frequency in pi units'); title('Imaginary Part')

V D 3.5: Cho x(n) = (0.9 exp (j /3))n , 0 . Xc nh X( ) v tnh

tun hon ca n.

Code:

KT QU

n = 0:10; x = (0.9*exp(j*pi/3)).^n;

k = -200:200; w = (pi/100)*k;X = x * (exp(-j*pi/100)) .^ (n'*k);

magX = abs(X); angX =angle(X);

subplot(2,1,1); plot(w/pi,magX);grid

xlabel('frequency in units of pi'); ylabel('|X|')

title('Magnitude Part')

subplot(2,1,2); plot(w/pi,angX/pi);grid

xlabel('frequency in units of pi'); ylabel('radians/pi')

title('Angle Part')

V D 3.6 : Cho x(n) = 2n , 10 .Tm hiu tnh cht lin hp i xng

ca bin i Fourier ri rc thi gian

Code:

Kt qu:

KT QU

n = -5:5; x = (-0.9).^n;k = -200:200; w = (pi/100)*k;

X = x * (exp(-j*pi/100)) .^ (n'*k);

magX = abs(X); angX =angle(X);

subplot(2,1,1); plot(w/pi,magX);grid; axis([-2,2,0,15])

xlabel('frequency in units of pi'); ylabel('|X|')

title('Magnitude Part')

subplot(2,1,2); plot(w/pi,angX/pi);grid; axis([-2,2,-1,1])

xlabel('frequency in units of pi'); ylabel('radians/pi')

title('Angle Part')

V D 3.7 : Trong v d ny,chng ta s xc minh tnh cht tuyn tnh (3.5)

bng cch s dng gi tr thc trong chui thi gian hu hn. x1(n) v x2(n) l

2 chui ngu nhin thng nht c phn chia gia [0,1] vi 0 n 10. Sau

chng ta c th s dng s bin i Fourier thi gian ri rc theo

phng php nh sau :

Code:

V D 3.8 : Cho x(n) l mt chui ngu nhin phn b ng u gia [0,1] vi

0 n 10 v cho y(n) = x(n-2). Sau chng ta c th xc nh c tnh thay

i mu (3.6) nh sau :

x1 = rand(1,11); x2 = rand(1,11); n = 0:10;

alpha = 2; beta = 3; k = 0:500; w = (pi/500)*k;

X1 = x1 * (exp(-j*pi/500)).^(n'*k); % DTFT of x1

X2 = x2 * (exp(-j*pi/500)).^(n'*k); % DTFT of x2

x = alpha*x1 + beta*x2; % Linear combination of x1 & x2

X = x * (exp(-j*pi/500)).^(n'*k); % DTFT of x

% verification

X_check = alpha*X1 + beta*X2; % Linear Combination of X1 & X2

error = max(abs(X-X_check)) % Difference

error =

7.3241e-15

x = rand(1,11); n = 0:10;

k = 0:500; w = (pi/500)*k;


% signal shifted by two samples

y = x; m = n+2;

Y = y * (exp(-j*pi/500)).^(m'*k); % DTFT of y

% verification

Y_check = (exp(-j*2).^w).*X; % multiplication by exp(-j2w)

error = max(abs(Y-Y_check)) % Difference

error =

5.7756e-15

V D 3.9 : xc nh c tnh thay i tn s (3.7), chng ta s s dng

phng php th : X(n)= cos(

) , 0 n 100 v

y(n)= x(n)

Code:

Kt qu:

n = 0:100; x = cos(pi*n/2);

k = -100:100; w = (pi/100)*k; % frequency between -pi and +pi


%

y = exp(j*pi*n/4).*x; % signal multiplied by exp(j*pi*n/4)

Y = y * (exp(-j*pi/100)).^(n'*k); % DTFT of y

% Graphical verification

subplot(2,2,1); plot(w/pi,abs(X)); grid; axis([-1,1,0,60])

xlabel('frequency in pi units'); ylabel('|X|')

title('Magnitude of X')

subplot(2,2,2); plot(w/pi,angle(X)/pi); grid; axis([-1,1,-1,1])

xlabel('frequency in pi units'); ylabel('radiands/pi')

title('Angle of X')

subplot(2,2,3); plot(w/pi,abs(Y)); grid; axis([-1,1,0,60])

xlabel('frequency in pi units'); ylabel('|Y|')

title('Magnitude of Y')

subplot(2,2,4); plot(w/pi,angle(Y)/pi); grid; axis([-1,1,-1,1])

xlabel('frequency in pi units'); ylabel('radians/pi')

title('Angle of Y')

V D 3.10 : th li tnh cht kt hp ( ) ( ), cho x(n) l mt

chui ngu nhin cc gi tr phc t -5 n 10 vi thc v phn o u c

ph n phi gia 0,1 . im chng vi MATLAP nh sau :

Code:

V D 3.11 : xc nh thuc tnh 3.9. Cho x (n) l mt chui ngu nhin

trn -5 n 10 v phn b ng u gia [0,1] .

n = -5:10; x = rand(1,length(n)) + j*rand(1,length(n));



% conjugation property

y = conj(x); % signal conjugation

Y = y * (exp(-j*pi/100)).^(n'*k); % DTFT of y

% verification

Y_check = conj(fliplr(X)); % conj(X(-w))


error =

8.6764e-14

n = -5:10; x = rand(1,length(n));



% folding property

y = fliplr(x); m = -fliplr(n); % signal folding

Y = y * (exp(-j*pi/100)).^(m'*k); % DTFT of y

% verification

Y_check = fliplr(X); % X(-w)


error =

1.7902e-15

V D 3.12 : T ong bi ton ny chng ta th i tnh cht ph p i xng (

3.10 );

x(n) = sin(n/2), 5 n 10

n = -5:10; x = sin(pi*n/2);



% signal decomposition

[xe,xo,m] = evenodd(x,n); % even and odd parts

XE = xe * (exp(-j*pi/100)).^(m'*k); % DTFT of xe

XO = xo * (exp(-j*pi/100)).^(m'*k); % DTFT of xo

% verification

XR = real(X); % real part of X

error1 = max(abs(XE-XR)) % Difference

error1 =

6.4862e-14

n = -5:10; x = sin(pi*n/2);



% signal decomposition

[xe,xo,m] = evenodd(x,n); % even and odd parts

XE = xe * (exp(-j*pi/100)).^(m'*k); % DTFT of xe

XO = xo * (exp(-j*pi/100)).^(m'*k); % DTFT of xo

% verification

XR = real(X); % real part of X

error1 = max(abs(XE-XR)) % Difference

error1 =

6.4862e-14

XI = imag(X); % imag part of X

error2 = max(abs(XO-j*XI)) % Difference

error2 =

6.4492e-14

% graphical verification

subplot(2,2,1); plot(w/pi,XR); grid; axis([-1,1,-2,2])

xlabel('frequency in pi units'); ylabel('Re(X)');

title('Real part of X')

subplot(2,2,2); plot(w/pi,XI); grid; axis([-1,1,-10,10])

xlabel('frequency in pi units'); ylabel('Im(X)');

title('Imaginary part of X')

subplot(2,2,3); plot(w/pi,real(XE)); grid; axis([-1,1,-2,2])

xlabel('frequency in pi units'); ylabel('XE');

title('Transform of even part')

subplot(2,2,4); plot(w/pi,imag(XO)); grid; axis([-1,1,-10,10])

xlabel('frequency in pi units'); ylabel('XO' title('Transform of odd part')

EXAMPLE 3.13 : p ng tn s H( ) ca h thng c t ng bi , h(n) =

( ) ( ) .

Kt qu

w = [0:1:500]*pi/500; % [0, pi] axis divided into 501 points.

H = exp(j*w) ./ (exp(j*w) - 0.9*ones(1,501));

magH = abs(H); angH = angle(H);

subplot(2,1,1); plot(w/pi,magH); grid;

xlabel('frequency in pi units'); ylabel('|H|');

title('Magnitude Response');

subplot(2,1,2); plot(w/pi,angH/pi); grid

xlabel('frequency in pi units'); ylabel('Phase in pi Radians');

title('Phase Response');

EXAMPLE 3.15 Mt h thng LTI c a a cc phng t nh khc bit,

Y(n)=0.8y(n-1)+x(n)

a.xc inh H( ).

b. xc nh v v th ( ) x(n)=cos(0.05 ) ( )

vit li phng t nh khc nh y(n) -0.8y(n-1)=x(n)

KT QU

subplot(1,1,1)

b = 1; a = [1,-0.8];

n=[0:100];x = cos(0.05*pi*n);

y = filter(b,a,x);

subplot(2,1,1); stem(n,x);

xlabel('n'); ylabel('x(n)'); title('Input sequence')

subplot(2,1,2); stem(n,y);

xlabel('n'); ylabel('y(n)'); title('Output sequence')

EXAMPLE 3.16 : Y(n)=0.0181x(n) +0.0543x(n-1) + 0.0543x(n-2) +0.0181x(n-

3)+ 1.7y(n-1) 1.1829y(n-2) + 0.2781y(n-3) Biu din cc cng v p ng

pha ca b lc ny v chng minh n l mt b lc, chng ta s biu din trn

Malab

KT QU

b = [0.0181, 0.0543, 0.0543, 0.0181]; % filter coefficient array b

a = [1.0000, -1.7600, 1.1829, -0.2781]; % filter coefficient array a

m = 0:length(b)-1; l = 0:length(a)-1; % index arrays m and l

K = 500; k = 0:1:K; % index array k for frequencies

w = pi*k/K; % [0, pi] axis divided into 501 points.

num = b * exp(-j*m'*w); % Numerator calculations

den = a * exp(-j*l'*w); % Denominator calculations

H = num ./ den; % Frequency response

magH = abs(H); angH = angle(H); % mag and phase responses

subplot(2,1,1); plot(w/pi,magH); grid; axis([0,1,0,1])

xlabel('frequency in pi units'); ylabel('|H|');

title('Magnitude Response');

subplot(2,1,2); plot(w/pi,angH/pi); grid

xlabel('frequency in pi units'); ylabel('Phase in pi Radians');

title('Phase Response');

EXAMPLE 3.18 cho xa(t)=e-1000|t|

xc nh v v Fourier ca n bin i dng

Matlap

Kt Qu:

% Analog Signal

Dt = 0.00005; t = -0.005:Dt:0.005; xa = exp(-1000*abs(t));

% Continuous-time Fourier Transform

Wmax = 2*pi*2000; K = 500; k = 0:1:K; W = k*Wmax/K;

Xa = xa * exp(-j*t'*W) * Dt; Xa = real(Xa);

W = [-fliplr(W), W(2:501)]; % Omega from -Wmax to Wmax

Xa = [fliplr(Xa), Xa(2:501)]; % Xa over -Wmax to Wmax interval

subplot(2,1,1);plot(t*1000,xa);

xlabel('t in msec.'); ylabel('xa(t)')

title('Analog Signal')

subplot(2,1,2);plot(W/(2*pi*1000),Xa*1000);

xlabel('Frequency in KHz'); ylabel('Xa(jW)*1000')

title('Continuous-time Fourier Transform')

EXAMPLE 3.19

Kt Qu

% Analog Signal

Dt = 0.00005; t = -0.005:Dt:0.005; xa = exp(-1000*abs(t));

% Discrete-time Signal

Ts = 0.0002; n = -25:1:25; x = exp(-1000*abs(n*Ts));

% Discrete-time Fourier transform

K = 500; k = 0:1:K; w = pi*k/K;

X = x * exp(-j*n'*w); X = real(X);

w = [-fliplr(w), w(2:K+1)]; X = [fliplr(X), X(2:K+1)];

subplot(2,1,1);plot(t*1000,xa);

xlabel('t in msec.'); ylabel('x1(n)')

title('Discrete Signal'); hold on

stem(n*Ts*1000,x); gtext('Ts=0.2 msec'); hold off

subplot(2,1,2);plot(w/pi,X);

xlabel('Frequency in pi units'); ylabel('X1(w)')

title('Discrete-time Fourier Transform')

EXAMPLE 3.21

Kt Qu:

error =

0.0363

EXAMPLE 3.22

KT QU

error =

0.1852

% Discrete-time Signal x1(n)

Ts = 0.0002; n = -25:1:25; nTs = n*Ts; x = exp(-1000*abs(nTs));

Fs=1/Ts;

% Analog Signal reconstruction

Dt = 0.00005; t = -0.005:Dt:0.005;

xa = x * sinc(Fs*(ones(length(n),1)*t-nTs'*ones(1,length(t))));

% check

error = max(abs(xa - exp(-1000*abs(t))))

% Discrete-time Signal x2(n)


% Analog Signal reconstruction

Dt = 0.00005; t = -0.005:Dt:0.005;

xa = x * sinc(Fs*(ones(length(n),1)*t-nTs'*ones(1,length(t))));

% check

error = max(abs(xa - exp(-1000*abs(t))))

EXAMPLE 3.23

Kt Qu:

% Discrete-time Signal x1(n) : Ts = 0.0002


% Plots

subplot(2,1,1); stairs(nTs*1000,x);


title('Reconstructed Signal from x1(n) using zero-order-hold'); hold on

stem(n*Ts*1000,x); hold off

%

% Discrete-time Signal x2(n) : Ts = 0.001


% Plots

subplot(2,1,2); plot(nTs*1000,x);


title('Reconstructed Signal from x2(n) using zero-order-hold'); hold on

stem(n*Ts*1000,x); hold off

Phn Bi Tp Chng 3

P 3.11 : i vi mi tuyn tnh, h thng thay i bt bin c m t bi cc p

ng xung, xc nh chc nng p ng tn s H(ejw). V p ng bin |H(ejw)|

v p ng pha H(ejw) trn khong :

Dng hm dtft

% P3.11

colordef white; clear; clc;

M = 250; k = -M:M; w = (pi/M)*k; % [0, pi] axis divided into 501 points.

w0 = pi/2; figure(1);

n = -50:50;

%P3.11.1

h = (0.9).^(abs(n));

H = dtft(h,n,w);

subplot(3,2,1); plot(w/pi,abs(H),'k');

xlabel('frequency in pi units'); ylabel('|H|'); title('Magnitude Response');

subplot(3,2,2); plot(w/pi,angle(H)/pi,'k');

xlabel('frequency in pi units'); ylabel('\Theta'); title('Phase Response');

%P3.11.2

h = sinc(0.2*n).*((stepseq(-20,-50,50)-stepseq(20,-50,50)));

H = dtft(h,n,w);





%P3.11.3

h = sinc(0.2*n).*((stepseq(0,-50,50)-stepseq(40,-50,50)));

H = dtft(h,n,w);





%P3.11.4

figure(2);

h = ((0.5).^n+(0.4).^n).*stepseq(0,-50,50);

H = dtft(h,n,w);





%P3.11.5

h = (0.5).^(abs(n)).*cos(0.1*pi*n);

H = dtft(h,n,w);





Khng dng hm dfft

% P3.11.2

k=-500:500;n = -20:20; w=(pi/500)*k

h = sinc(0.2*n);

H = h * (exp(-j*pi/500)) .^ (n'*k);





%P3.11.3

k=-500:500;n = 0:39; w=(pi/500)*k

h = sinc(0.2*n);

H = h * (exp(-j*pi/500)) .^ (n'*k);





Chng 4

Bin i Z- (Z ngc)

P4.2 Cho chui x(n) = (0.9)n cos( n/4)u(n) .

( ) { (

)

1. Chng t Z ngc Y(z) ca y(n) c biu din theo Z ngc X(z) ca x(n)

l Y(z) = X(z2)

2. Xc nh Y(z)

3. Dng Matlab kim chng rng dy y(n) c bin i Z ngc Y(z)

Bi lm

1. Ta c :

( ) ( )

( ) ( )

M, ( ) ( ) nn :

( ) ( )

( ) ( )

( )

2. Ta C: x(n) = (0.9)n cos( n/4)u(n)

suy ra : ( )

Hay: ( )

(do Y(z) = X(z2) )

Code

Kt qu:

%P4.2

b = [1,0,-0.9*sqrt(2)/2,0,0]; a=[1,0,-0.9*sqrt(2),0,0.81]; [R,p,C] = residuez(b,a)

w=[0:1:500]*pi/500; Y = freqz(b,a,w);

magY = abs(Y); phaY = angle(Y);

subplot(2,1,1); plot(w/pi,magY); grid

xlabel('frequency in pi units'); ylabel('Magnitude')

title('Magnitude Response')

subplot(2,1,2); plot(w/pi,phaY/pi); grid

xlabel('frequency in pi units'); ylabel('Phase in pi units')

title('Phase Response')

P4.21 Mt b lc k thut s c m t bi hm p ng tn s

( ) ( ) ( ) (

)

To 200 mu ca tn hiu x(n) = sin( n/2) + 5cos( n), v x l thng qua cc b

lc c c y(n) . So snh phn trng thi n nh y(n) vi x(n). bin v

pha b nh hng nhu the nao bi cc b lc .

Bi Lm

Ta c :

( )

Hay : y(n) = 3x(n) + 2x(n-1) + 6x(n-2) + 3x(n-3) + 5x(n-4) + 3x(n-5)

%P4.21

subplot(1,1,1)

b = [3,2,6,3,5,3]; a = [1]; n = [0:200];

x =sin(n*pi/2)+ 5*cos(n*pi); y = filter(b,a,x);

subplot(2,1,1); stem(n,x);

xlabel('n'); ylabel('x(n)'); title('Input sequence')

subplot(2,1,2); stem(n,y);

xlabel('n'); ylabel('y(n)'); title('Output sequence')

Chng 7

Thit k b lc FIR

V D 7.4 :

Cho h(n) = {-4, 1, -1, -2, 5, 6, 5, -2, -1, 1, -4}. Xc nh cc p ng bin

Hr v v tr cc cc khng ca H(z).

Bi lm

T M=11 l s l v t h(n) i xng ( ) = 5 , nn l b lc tuyn

tnh FIR Type-1

M :

( ) ( )

( )

Vi

( ) (

) ( ) (

)

Do :

( )

% Vi Du 7.4

h = [-4,1,-1,-2,5,6,5,-2,-1,1,-4];

M = length(h); n = 0:M-1;

[Hr,w,a,L] = Hr_Type1(h);

a,L;

amax = max(a)+1; amin = min(a)-1;

subplot(2,2,1); stem(n,h); axis([-1 2*L+1 amin amax])

xlabel('n'); ylabel('h(n)'); title('Impulse Response')

subplot(2,2,3); stem(0:L,a); axis([-1 2*L+1 amin amax])

xlabel('n'); ylabel('a(n)'); title('a(n) coefficients')

subplot(2,2,2); plot(w/pi,Hr);grid

xlabel('frequency in pi units'); ylabel('Hr')

title('Type-1 Amplitude Response')

subplot(2,2,4); zplane(h,1)% thay zplane cho pzplo

V D 7.8 :

Thit k mt b lc thng thp FIR k thut s vi cc thng s k thut sau

y :

Chn mt ca s chc nng thch hp t bng 7.1. Xc nh cc xung p ng

v cung cp mt th ca p ng tn s ca b lc thit k.

% Vi Du 7.8

wp = 0.2*pi; ws = 0.3*pi; tr_width = ws - wp;

M = ceil(6.6*pi/tr_width) + 1

n=[0:1:M-1];

wc = (ws+wp)/2, % Ideal LPF cutoff frequency

hd = ideal_lp(wc,M); w_ham = (hamming(M))'; h = hd .* w_ham;

[db,mag,pha,grd,w] = freqz_m(h,[1]); delta_w = 2*pi/1000;

Rp = -(min(db(1:1:wp/delta_w+1))); % Actual Passband Ripple

As = -round(max(db(ws/delta_w+1:1:501))) % Min Stopband attenuation

% plots

subplot(2,2,1); stem(n,hd); title('Ideal Impulse Response')

axis([0 M-1 -0.1 0.3]); xlabel('n'); ylabel('hd(n)')

subplot(2,2,2); stem(n,w_ham);title('Hamming Window')

axis([0 M-1 0 1.1]); xlabel('n'); ylabel('w(n)')

subplot(2,2,3); stem(n,h);title('Actual Impulse Response')

axis([0 M-1 -0.1 0.3]); xlabel('n'); ylabel('h(n)')

subplot(2,2,4); plot(w/pi,db);title('Magnitude Response in dB');grid

axis([0 1 -100 10]); xlabel('frequency in pi units'); ylabel('Decibels')

CCS (Code Composer Studio)

Bi 1 : Thit k mt sng sin m thanh sao cho fton = 9,6k ( vi fs = 96k )

Bi lm

Ta c :

Li c :

( )

T : sine_table [10] = {0,588,951,951,588,0,-588,-951,-951,-588}

//Sine8_LED.c Sine generation with DIP switch control

#include "dsk6416_aic23.h" //support file for codec,DSK

Uint32 fs = DSK6416_AIC23_FREQ_96KHZ;//set sampling rate

short loop = 0;

short i=0; //table index

short gain = 10; //gain factor

short sine_table[10]={0,588,951,951,588,0,-588,-951,-951,-588};//sine values

#define BUFFSIZE 128

// Global Variables

short gBuffer[BUFFSIZE];

void main()

{

//comm_poll(); //init DSK,codec,McBSP

c6416_dsk_init();

DSK6416_LED_init(); //init LED from BSL

DSK6416_DIP_init(); //init DIP from BSL

while(1) //infinite loop

for (i=0; i< BUFFSIZE; i++)

{

if(DSK6416_DIP_get(0)==0) //=0 if DIP switch #0 pressed

{

DSK6416_LED_on(0);//turn LED #0 ON

for (loop=0; loop

Kt qu

Bi 2 Thit k FIR

Bi lm

Code

//Fir.c FIR filter with the C6416 DSK. Include coefficient file

#include "lp1500_256.cof" //coefficient file

#include "dsk6416_aic23.h" //codec-dsk support file

Uint32 fs=DSK6416_AIC23_FREQ_48KHZ; //set sampling rate

int yn = 0; //initialize filter's

output

short dly[N];

short gbuffer[200]; //delay samples

interrupt void c_int11() //ISR

{

short i;

dly[0]=input_sample(); //input newest sample

yn = 0; //initialize filter's output

for (i = 0; i< N; i++)

yn += (h[i] * dly[i]); //y(n) += h(i)* x(n-i)

for (i = N-1; i > 0; i--) //starting @ end of buffer

dly[i] = dly[i-1]; //update delays with data move

output_sample((short)(yn>>15)); //scale output filter sample

gbuffer[i]=((short)(yn>>15));

return;

}

void main()

{

comm_intr(); //init DSK, codec, McBSP

while(1); //infinite loop

}

Documents

BÁO-CÁO-THỰC-HÀNH-THÍ-NGHIỆM-XỬ-LÍ-SỐ-TÍN-HIỆU-NHÓM-1