1. DATA COMMUNICATION
Lecture-13

2. Review of Lecture 12 Sine Waves and its Characteristics
Control of Signals
Time and Frequency Domain

3. Overview of Lecture 13 Composite Signals
Frequency Spectrum and Bandwidth
Other Definitions of Bandwidth
Digital Signals

4. Composite Signals

5. Frequency Spectrum and Bandwidth
Collection of all the component frequencies a signal contains
Bandwidth
Width of the Frequency Spectrum

6. How to calculate Bandwidth?

7. Example 4.8
If a periodic signal is decomposed into five sine waves with frequencies 100, 300, 500, 700, and 900 Hz, what is the Bandwidth?

8. Example 4.8
Solution:

9. Other Definitions of Bandwidth

10. 3 dB Bandwidth or Half Power Bandwidth
For the magnitude spectra of , the range of the spectrum that does not fall lower than times the max.

11. Equivalent Noise Bandwidth
The width of a fictitious rectangular spectrum created to have the same power in the rectangular band as the power of the signal in positive frequencies

12. Null-to-Null Bandwidth or Zero Crossing Bandwidth
If the maximum frequency in a spectrum is
,the first null above and below will be and , where is the Null-to-Null Bandwidth

13. Power Bandwidth
Frequency Band in which 99% of the total power resides

14. Bit Interval and Bit Rate
Bit Interval (seconds)
Time required to send one single bit
Bit Rate (bps)
Number of bits sent per second

15. Bit Interval and Bit Rate

16. Significant Spectrum and Significant Bandwidth

17. Summary Composite Signals Frequency Spectrum and Bandwidth
Other Definitions of Bandwidth
Digital Signals

18. Suggested Reading Section 4.4, 4.5, 4.6
“Data Communications and Networking” 2nd Edition by Behrouz A. Forouzan

19. DATA COMMUNICATION
Lecture-13