1
Why Digital Signal Processing?
Most signals are
CT (e.g., speech and
audio). But:
• digital computers are fast (real time in
many apps), efficient, and flexible and
• Several techniques such as encryption
(for security) and compression techniques
(for reducing data rate) are mostly
designed for digital data representations.
• In this class, we dealt only with discrete-
time signal processing
Review
*Discrete sequences, functions
*Notions of Linearity, Time Invariance, Relaxed,
Causality, BIBO, Periodic, Static/Dynamic
(memory), Symmetry, Energy and Power
Signals
*Solving the output for systems characterized by
difference equations; Block Diagrams
* Filters (FIR, IIR), minimum phase
* The Z-transform
Material: lecture notes, Chs. 1, 2, 3, 4, 5, 6, 9, 10,
and 11. and Homeworks 1-4. One 8.5 x 11 sheet
(double-sided) is allowed. Nothing electronic
(phones, calculators, etc.)
Operations on signals
• Discrete time signal often obtained by
sampling
a continuous-time signal
• Sequence
{
x
[
n
]}
=
x
a
(
nTs
),
n
=…-1,0,1,2…
•
Ts
= sampling period; 1/
T
= Fs, where Fs is
sampling frequency