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1
Physical Layer
Computer Networks
2
Where are we?
3
Numbering Systems
BinaryHexadecimalDecimal
4
Transmission of Information
From PhysicsEnergyElectromagnetic wave propogation
From MathematicsCoding Theory
5
Analog and Digital Signaling
6
Amplitude Modulation
7
Frequency Modulation
8
Baseband and Broadband
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Phase Modulation
10
Modems
11
Digital Encoding
12
CSU/DSU
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Undesirable Effects and Limitations
Propagation DelayBandwidthNoiseInterferenceDistortionAttenuation
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Sampling and Nyquist’s Theorem
15
Shannon’s Limit
Corrects for SNR
Encoding more bits per cycle time helps, but you cannot overcome the fundamental physical limits of a real transmission system.
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Timing
Asynchronousbit level
Synchronouscharacter level
Isochronoustiming coordination must be successful
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Transmission Media
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Connectors
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Media Test and Measurement
Hands-on Demo
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Repeaters
Signal RegenerationClean upAmpliflyDistance Extension
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Hubs
Repeater functionality, plus...Concentration PointSignal Distribution DeviceManagement Functions
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Throughput versus Bandwidth
Usable capacityDetermined by
engineering
Electrical PropertyDetermined by
physics
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