part 1 presentation 1
TRANSCRIPT
Signals and SystemsSignals and SystemsSignals and Systems
Tania Stathaki
Location: Room 811bExtension: 46229Email: [email protected]
LOGISTICS OF THE COURSE
• Duration
– 20-22 lectures
• Assessment
– 100% exam
– There isn't any coursework or homework
LOGISTICS OF THE COURSE
• Notes
– 9 Parts of Theory
– 9 Tutorial Sheets
• Text Book
– A. Oppenheim, A. Wilsky, S. Nawab, Signals
and Systems
What is a signal ?
The concept of signal refers to the space
or time variations in the physical state of
an object.
Applications
• Electrical Engineering
voltages/currents in a circuit
speech signals
image signals
• Physics
radiation
Applications (cont.)
• Mechanical Engineering
vibration studies
• Astronomy
space photos
Applications (cont.)
• BiomedicineEEG, ECG, MRI, X-Rays, Ultrasounds
• Seismologytectonic plate movement, earthquake prediction
• Economics
stock market data
Classification of signals
Continuous Time-Discrete Time
Continuous Time-Discrete Time
From Continuous to Discrete: Sampling
0 10 20 30 40 50 60-10
-5
0
5
10
Observed signal x(t)
continuous time
0 10 20 30 40 50 60-10
-5
0
5
10
discrete time
Observed signal x[n]
256x256 64x64
2 Dimensions
From Continuous to Discrete: Sampling
Analog-Digital
Analog signal
Digital signal
From Analog to Digital: Quantisation
Discrete (Sampled) and Digital (Quantized) Image
Discrete (Sampled) and Digital (Quantized) Image
256x256 256 levels 256x256 32 levels
Discrete (Sampled) and Digital (Quantized) Image
256x256 256 levels 256x256 2 levels
Discrete (Sampled) and Digital (Quantized) Image
Binary ImageBinary Image
Digital vs. Analog
Digital vs. Analog
Analog-Digital
Examples of analog technology
• photocopiers
• telephones
• audio tapes
• televisions (intensity and color info per scan line)
• VCRs (same as TV)
Examples of digital technology
• Digital computers!
Periodic-Aperiodic
Causal-Anticausal-Noncausal
Even-Odd
Even-Odd (cont.)
Even-Odd (cont.)
Even-Odd (cont.)
Deterministic-Stochastic
Right handed-Left handed
Finite length-Infinite Length
Electroencephalogram (EEG) Data
Stock Market Data
Satellite image
Volcano Kamchatka Peninsula, Russia
Satellite image
Volcano in Alaska
Medical Images:
MRI of normal brain
Medical Images:
X-ray knee
Medical Images: Ultrasound
Five-month Foetus (lungs, liver and bowel)
Astronomical images