Write a MATLAB program that takes a data sequence {Dk}, precodes it for a modified duobinary pulse transmission system to produce {pk}, and maps the precoded sequence into the transmitted amplitude levels {ak}. Then, from the transmitted sequence, form the received noise-free sequence {bk = ak – ak-2} and, using the relation given by (6.5.37), recover the data signal {Dk}. Run the program for any pseudorandom data sequence {Dk} for M = 2 and M = 4 transmitted amplitude levels and check the results