Network Technology 12nd - Physical Layer !Mario Lombardo - lombardo@informatik.dhbw-stuttgart.de

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understanding physical limitations 1.2 Introduction

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• ways of data transmission • acoustic • mechanical • electric • radio • optical

understanding physical limitations 1.2 What can we see here?

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understanding physical limitations 1.2 Resistor

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• what is a resistor? • something that conducts electrons • something that resists the flow of electrons • the amount of resistance is measured in Ohm

• invented by Georg Simon Ohm

understanding physical limitations 1.2 What can we see here?

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understanding physical limitations 1.2 Capacitor

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• what is a capacitor? • something that stores electrons in a voltage level • basically two surfaces without connection • capacity is measured in Farad

• invented by Michael Faraday

understanding physical limitations 1.2 What can we see here?

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understanding physical limitations 1.2 Inductor

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• what is an inductor? • a part that creates a magnetic field nearby • inductor is measured in Henry

• invented by Joseph Henry

understanding physical limitations 1.2 What can we see here?

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understanding physical limitations 1.2 Wire

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• what is a wire? • typical a low resistance conductor for electricity • additional it has the properties of a capacitor, an inductor

understanding physical limitations 1.2 Wire

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• what is a wire? • typical a low resistance conductor for electricity • additional it has the properties of a capacitor, an inductor

• parameters of a wire (uniform circuit) • inductance per unit length L‘ = L / s • capacitance per unit length C‘ = C / s • resistance per unit length R‘ = R / s • conductance per unit length G‘ = G / s

understanding physical limitations 1.2 What is the impact of having a uniform circuit?

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• impacts • signal looses strength • signal timing may be affected • an echo can influence following transmissions

understanding physical limitations 1.2 Physical implications

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• characteristic of a wave impedance

• factor of the reflected wave

• speed of propagation

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thank you. questions?