Principles of Telecommunications Technology

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Principles of Telecommunications Technology

• Chapter 2

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Objectives

• In this chapter, you will learn to
• Describe the principles of electricity that
  underlie all telecommunications signaling
• Explain the concepts of current and voltage as
  they apply to telecommunications technology
• Describe the components on an integrated circuit
• Explain the difference between analog and digital
  transmission
• Use binary encoding to represent decimal numbers
• Describe various electricity and data
  transmission measurements

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Atomic Charges

• Charge - the characteristic of a material that
  enables it to exert force on another material.
• Neutrons - found at the center of an atom,
  possess no charge and are said to be neutral.
• Protons - found at the center of an atom along
  with neutrons, carry a positive charge.
• Electrons - orbit the center of an atom and carry
  a negative charge

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Atomic Charges
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Static Electricity

• Static electricity - the release of an
  accumulated charge in some material or object.
• Because the charges inherent in electrons and
  protons are bound to balance each other through
  static electricity, these charges are also called
  electrostatic charges.

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Electric Current

• Electric current - the controlled movement of an
  electrical charge (or electrons) along the atoms
  of a conductor.
• Circuit - a closed connection between an electric
  source (such as a battery) and a load (such as a
  lamp) over which current may flow.
• Signal - occurs when current manipulated to
  transmit information.

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Electric Current

• Voltage - the pressure that the electric current
  exerts on its conductor is known. It is commonly
  equated to the strength of the electric current,
  and is measured in volts
• Amperes - the amount of current (or charge
  flowing through a wire each second ) is measured
  in amperes, abbreviated as amps.
• Resistance - a materials opposition to electric
  current.

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Electric Current
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Conductors and Insulators

• Conductor - a material over which electric
  current readily flows.
• Grounding - the use of a conductor (such as a
  wire) to divert unused or potentially harmful
  charges to an insulator, where they will be
  stopped or absorbed.
• Insulators - materials that do not allow electric
  current to flow easily.
• Semiconductor - conducts electricity better than
  an insulator, but not as well as a conductor.

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Conductors and Insulators
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Resistance
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Calculating Voltage, Amps, and Resistance with
Ohms Law
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Direct and Alternating Current

• Direct current (DC) - an electrical charge flows
  steadily in one direction over the conductor.

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Direct and Alternating Current

• Alternating current (AC) - the electrical charge
  flows in one direction first, then in the
  opposite direction, then back in the first
  direction, and so on, in an alternating fashion
  over the conductor.

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Direct and Alternating Current
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Direct and Alternating Current
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Capacitance

• The ability for an electric circuit or component
  to accumulate or store a charge.
• Capacitance is measured in Farads (abbreviated as
  F), a unit named after English chemist and
  physicist Michael Faraday, who experimented with
  electricity in the early 1800s.
• Capacitor - a device that stores electrical
  charge (as the tank stores water).

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Capacitance
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Capacitance
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Capacitance
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Capacitance
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Inductance
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Inductance
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Inductance
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Inductance
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Inductance
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Inductance
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Electrical Power
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Electrical Power
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Measuring Electricity
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Measuring Electricity
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Measuring Electricity
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Passive Electronic Devices

• Passive device - a component that contributes no
  power gain to a circuit.
• Resistor - a component inserted into a circuit to
  provide a specific amount of resistance

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Diodes
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Diodes
Diode
LED
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Transistors
NPN Transistor
PNP Transistor
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Integrated Circuits

• Circuits that combine the conductor and the
  attached components of a circuit in one small
  unit.

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Analog Transmission

• Analog - electromagnetic signals that
  continuously vary in their strength and speed.

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Analog Signal
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Digital Transmission

• Digital Signal
• Individual pulses of voltage

1
1
Volts
0
0
Time
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Transmission Flaws

• Noise - unwanted interference from external
  sources, which can degrade or distort a signal.
• Attenuation - the loss of a signals strength as
  it travels away from its source.
• Amplifier - an electronic device that increases
  the voltage, or power, of the signals.
• Regeneration - when digital signals are repeated,
  they are actually retransmitted in their
  original, pure form, without any noise.
• Repeater - a device that regenerates a digital
  signal.

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Transmission Flaws
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Transmission Flaws
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Encoding and the Numbering System

• Encoding - the process of modifying data so that
  it can be interpreted by the receiver.
• Methods for encoding data include
• The Decimal System
• The Binary System http//en.wikipedia.org/wiki/Bin
  ary_numeral_system
• Hexadecimal System http//en.wikipedia.org/wiki/He
  xadecimal
• EBCDIC (8bit)
• ASCII (8 bit)
• UNICODE (16 bit)

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Measuring Data
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Throughput and Bandwidth

• Throughput - the amount of data that a
  communications channel can carry during a given
  period of time.
• The physical nature of every communications
  channel determines its potential throughput.
• Bandwidth - a measure of the difference between
  the highest and lowest frequencies that a media
  can transmit.

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Summary

• Electricity may exist as either static
  electricity, the imbalance of charges, or as
  current electricity, the flow of charge along a
  conductor.
• The three main characteristics of a circuit are
  voltage, current, and resistance. If two of these
  characteristics are known, the third can be
  calculated using Ohms Law.
• Electronic devices may be active or passive.
  Examples of passive devices are capacitors and
  inductors. Examples of active devices are
  transistors and diodes.