Digital Signal Processing Reference
In-Depth Information
Exercises on Chapter 11
Exercise 1
Explain using concrete examples the enormous appetite of multimedia applications for
transmission capacity. What importance could ADSL have as a medium-term solution.
Exercise 2
The term "encoding" does not exist in analog technology. Give a meaningful definition of
this term.
Exercise 3
ASCII encoding is a long-established standard. Summarize why it is regarded as obsolete
and what qualities a new standard shoulod have.
Exercise 4
Audio and video signals are lossily compressed, but program and text files are not. Try to
show the boundary between the two kinds of compression. Why is compression not
always loss-free?
Exercise 5
Check using the example of Illustration 224 whether this HUFFMAN code is an “opti-
mum” code, by producing a different HUFFMAN tree (e.g. take "0" instead of "00" for A)
Exercise 6
Carry out the LZW encoding for "the rain in Spain falls mainly on the plain".
Exercise 7
Explain the virtues of delta and sigma-delta encoding. Under what conditions does this
encoding make sense with audio signals compared with the traditional PCM process?
Why are 1 bit-converters gaining more and more ground?
Exercise 8
Describe the structure and purpose of a "decimation filter" at the output of a sigma-delta-
encoder.
Exercise 9
Explain the psycho-acoustic effects which are exploited in the MPEG encoding of audio
signals (irrelevance reduction).
Exercise 10
In MPEG audio compression the input signal is distributed over 32 equal frequency
bands. What is this intended to achieve?
