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- Digital Signal Processing - DSP
- Practical
**SVS Institute of Technology - SVSIT**- Electronics and Communication Engineering
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III Year B.Tech. ECE - II Sem DIGITAL SIGNAL PROCESSING LAB 1. Generation of Sinusoidal waveform / signal based on recursive difference equations 2. To find DFT / IDFT of given DT signal 3. To find frequency response of a given system given in (Transfer Function/ Differential equation form). 4. Implementation of FFT of given sequence 5. Determination of Power Spectrum of a given signal(s). 6. Implementation of LP FIR filter for a given sequence 7. Implementation of HP FIR filter for a given sequence 8. Implementation of LP IIR filter for a given sequence 9. Implementation of HP IIR filter for a given sequence 10. Generation of Sinusoidal signal through filtering 11. Generation of DTMF signals 12. Implementation of Decimation Process 13. Implementation of Interpolation Process 14. Implementation of I/D sampling rate converters 15. Audio application such as to plot a time and frequency display of microphone plus a cosine using DSP. Read a .wav file and match with their respective spectrograms. 16. Noise removal: Add noise above 3 KHz and then remove, interference suppression using 400 Hz tone. 17. Impulse response of first order and second order systems Experiments beyond the syllabus: 1. Linear convolution. 2. Circular convolution. 1

EXP.NO: 1 GENERATE SINUSOIDAL WAVEFORM BASED ON RECURSIVE DIFFERENCE EQUQTIONS Aim: Generation of Sinusoidal waveform / signal based on recursive difference equations EQUIPMENTS: PC with windows (95/98/XP/NT/2000). MATLAB Software THEORY: For the given difference equation, a sinusoidal signal/sequence is applied as the input. Using the given initial conditions, the sinusoidal response of the given discrete system is to be computed. 1. The difference equation is y(n)=x(n)+y(n-1), which is a first order system, with the initial condition y(-1)=4. PROGRAM: I=input ('Enter the value of initial condition y(-1)') n=0:0.001:1 f=input ('Enter the frequency') x=sin (2*pi*f*n) y=zeros (1, length(n)) for i=1:length(n) y(i)=x(i)+I I=y(i) end subplot(2,1,1) plot(n,x) title('Input signal x(n) applied') xlabel('Time') ylabel('Amplitude') subplot(2,1,2) plot(n,y) title('Sinusoidal Response of the given first order system') xlabel('Time') ylabel('Amplitude') Enter the value of initial condition y(-1) I=4 Enter the frequency f =10 2

Input signal x(n) applied 1 0.5 Amplitude 0 -0.5 -1 0 0.1 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Time Sinusoidal Response y(n) of the given first order system 0.2 0.3 0.4 1 40 Amplitude 30 20 10 0 0.5 Time 3 0.6 0.7 0.8 0.9 1

EXP.NO: 2 DFT/IDFT OF GIVEN DT SIGNAL Aim: To find DFT/IDFT of a given Discrete Time signal EQUIPMENTS: PC with windows (95/98/XP/NT/2000). MATLAB Software THEORY: The discrete Fourier Transform of sequence is Periodic and we are interested in frequency range 0 to 2π there are infinitely many ω in this range. If we use a digital computer to compute N equally spaced points over the interval 0≤ ω<2π then the N points should be located at ω k = (2π/N)k; k=0,1,2……,N-1; These N equally space frequency samples of the DTFT are known as DFT denoted by X(k) is X(k) = X(ejω)| ω k = (2π/N)k ; 0≤k≤N-1. The formulas for DFT and IDFT are 0 ≤ k ≤ N-1. DFT 0 ≤ N ≤ N-1. IDFT For notation purpose = DFT [ = IDFT [ ] ] PROGRAM: %DFT function function X=dft( x, N); L=length(x); if(N<L) error('N must be >=L') end x1=[x zeros(1,N-L)]; for k=0:1:N-1; for n=0:1:N-1; p=exp(-i*2*pi*n*k/N); 4

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