1. Lab No.10
Discrete time Fourier transform
(Frequency response)
Designed by : Dawar Awan
dawar@cecos.edu.pk
CECOS College of Engineering and IT
March – July 2012

2. DTFT : Example
CECOS College of Engineering and IT
March – July 2012

3. DTFT : Example
CECOS College of Engineering and IT
March – July 2012

4. DTFT : Example
CECOS College of Engineering and IT
March – July 2012

5. DTFT : Example
CECOS College of Engineering and IT
March – July 2012

6. DTFT : Example
CECOS College of Engineering and IT
March – July 2012

7. DTFT : Example
CECOS College of Engineering and IT
March – July 2012

8. Task
1. Repeat DTFT_example for three other values of
frequency
CECOS College of Engineering and IT
March – July 2012

9. DTFT Properties
 Time Shifting(Program12_2)
x[n-no] ↔ e-jωn0X(ejω)
CECOS College of Engineering and IT
March – July 2012

10. DTFT Properties
 Time Shifting(Program12_2)
CECOS College of Engineering and IT
March – July 2012

11. Task
1. Run Program12_2, and comment on your results
2. Run the program for some other values of time shift
3. Run the program for some other sequences
CECOS College of Engineering and IT
March – July 2012

12. DTFT Properties
 Frequency Shifting(Program12_3)
ejω0nx[n] ↔ X(ej(ω-ω0))
CECOS College of Engineering and IT
March – July 2012

13. DTFT Properties
 Frequency Shifting(Program12_3)
CECOS College of Engineering and IT
March – July 2012

14. Task
1. Run Program12_3, and comment on your results
2. Run the program for some other values of frequency
shift
3. Run the program for some other sequences
CECOS College of Engineering and IT
March – July 2012

15. DTFT Properties
 Convolution(Program12_4)
x[n]*h[n] ↔ X(ejω) H(ejω)
CECOS College of Engineering and IT
March – July 2012

16. DTFT Properties
 Convolution(Program12_4)
CECOS College of Engineering and IT
March – July 2012

17. Task
1. Run Program12_3, and comment on your results
2. Run the program for some other sequences
CECOS College of Engineering and IT
March – July 2012

18. DTFT Properties
 Time reversal(Program12_5)
x[-n] ↔ X(e-jω)
CECOS College of Engineering and IT
March – July 2012

19. DTFT Properties
 Time reversal(Program12_5)
CECOS College of Engineering and IT
March – July 2012

20. Task
1. Run Program12_3, and comment on your results
2. Run the program for some other sequences
CECOS College of Engineering and IT
March – July 2012