Answer the following questions about recording of the sound wave above onto a CD or DVD.

 

1.) In order to convert the above analog signal to a digital signal, the amplitude of the sound wave is _______________________

 

2.)  What can you tell me about the sound at point A, B, and C?

 

3.)  A CD player reads the CD and sees an 8 digit binary number of 10001011.  What amplitude does this represent?

 

4.) What is the eight bit binary number for an amplitude of 115?

 

5.)  In order to read the information on the disc, the detection system looks for changes in reflection of the laser off the CD.  What produces a 1?

 

6.)  The amplitude of an audio signal is translated onto a CD as __________, and the louder the sound the _________________.

 

7.)  How are the width of the pits and lands (digital information) on a CD related to the laser which reads them?  

 

8.) What has changed with the advent of DVDs?

 

9.)  Name the major parts of an optical communication system.

 

10.)  How is a digitized signal sent across the country with fiber optics communication?

 

11.)  What do the routers, multiplexers, and de-multiplexers do?

 

12.)  Match the optical components which are needed for each step in a digital optical communication system.

Basics:                                                                                                  Optical Components:

Digitize Message                                                                       Amplifier         

Imprint Message                                                                       Photodiode and Computer

Send Digitized Message                                                            Computer and Modulator

Detect Message                                                                        Laser   

Decode Message                                                                      Fiber and Lenses

 


13.)  What will happen to Ray A, B, and C inside the fiber optic cable?  Why?

 

14.)  If a fiber loses 10% of its light every 100 km due to absorption into the O-H vibration, how much light is left after 500 km?  Let’s assume it starts with an amplitude of 100.