Digital Signal Processing Reference
In-Depth Information
Exercises on Chapter 12
Exercise 1
List the types of files which it is especially necessary to protect against defective
transmission. In what context does the concept of redundancy occur?
Exercise 2
Define the concept of the (HAMMING) distance of a code and describe its importance
for error recognition and correction. What is the significance of the inequality 2
k
= n + 1
(k check bits; n is the length of the code word).
Exercise 3
Explain the maximum likelihood method for the recognition and correction of
transmission errors.
Exercise 4
Create an example (as in Illustration 251) and determine the correction and check bits via
“modula 2 addition”.
Exercise 5
Describe the principle of convolutional encoding as compared with block encoding.
Exercise 6
Explain in connection with convolutional encoding the representation of the signal flow
as a state diagram or a trellis diagram.
Exercise 7
Describe the strategy of the VITERBI decoding of a defective bit pattern reception se-
quence in the trellis diagram by means of the state diagram
Exercise 8
Soft decision is usually advantageous compared with hard decision. Explain.
Exercise 9
Formulate and interpret SHANNON's main thesis in encoding theory.
