Answer the following questions. This is due by email to
jstanton@gwu.edu by Tuesday, March 2nd before class starts.

1. How does NRZ-L differ from NRZ-I?

2. What is the major disadvantage of NRZ encoding? How does RZ or
   biphase encoding solve it?

3. For each of the encodings: unipolar, NRZ-L, NRZ-I, RZ, and
   Manchester encode the following bit patterns (show the drawing of
   voltage levels) and write down how many transitions there are.  
   *) 000000 
   *) 111111 
   *) 010101

4. What is the basic unit of conversion used in 4-PSK and 16-QAM
   modulation? 

5. List the Baud and Bit rate for ASK, 8-QAM, and 16-QAM. Why do they
   differ in some cases?