Transcript Periodic signal - Kean University

Periodic signal

A signal is periodic if and only if
s(t + T) = s(t) for all values of t
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T is the period of the signal.
Analog signal
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An analog signal is a continuously varying
electromagnetic wave that may be propagated
over a variety of media, depending on spectrum.
Digital signal
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A digital signal is a sequence of voltage pulses
that may be transmitted over a wire medium.
Characteristics of a periodic
signal
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Amplitude
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Frequency
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instantaneous value of a signal at any time.
the inverse of the period (1/T), or the number of
repetition of the period per second; it is expressed
in cycles per second, or hertz (Hz).
Phase
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measure of the relative position in time within a
single period of a signal.
Spectrum and bandwidth
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Spectrum of a signal is the range of frequencies
that it contains.
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Bandwidth of a signal is the width of the
spectrum in which most of the energy in the
signal is contained.
Transmission
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Data transmission occurs between transmitter
and receiver over some transmission medium.
Transmission media may be classified as guided
or unguided.
Guided media
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With guided media, the wave are guided along a
physical path; example of guided media are:
twisted pair
 coaxial cable
 optical fiber
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Unguided media
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Unguided media provide a means for
transmitting electromagnetic waves but do not
guide them; examples are propagation through:
air
 vacuum
 seawater
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Direct link
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The term direct link is used to refer to the
transmission path between two devices in which
signals propagate directly from transmitter to
receiver with no intermediate devices, other than
amplifier or repeaters used to increase signal
strength.
Point-to-Point
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A guided transmission medium is point-to-point
if it provides a direct link between two devices
and those are the only two devices sharing the
medium.
Point-to-Point
Transmitter/
receiver
Medium
Amplifier
or repeater
0 or
more
Transmitter/
receiver
Medium
Multipoint
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In a multipoint guided configuration, more than
two devices share the same medium.
Multipoint
Transmitter/ …. Transmitter/
receiver
receiver
Medium
Transmitter/
receiver
Amplifier
or repeater
Transmitter/
receiver
Medium
0 or more
Simplex transmission
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In simplex transmission, signals are transmitted
in only one direction; one station is transmitter
and the other is receiver.
Half-duplex transmission
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In half-duplex transmission, both station may
transmit, but only one at a time.
Full-duplex transmission
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In full-duplex transmission, both station may
transmit simultaneously. In this case the medium
is carrying signals in both direction.
Telecommunication Devices
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Modems
Fax modems
Special purpose modems
Multiplexers
TDM
 FDM
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Communication processors
Telecommunication Carriers &
Services
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Common carriers
AT&T
 MCI
 Sprint
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Value added carriers
Telnet
 SprintNet
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Switched Lines
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Switched line is a standard telephone line that
uses switching equipment to allow one
transmission device to be connected to other
transmission devices.
Dedicated Line
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Dedicated line is a line that provides a constant
connection between two points.
Private Branch Exchange
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PBX is a communications system that can
manage both voice and data transfer within a
building and to outside lines.
PBX can store calls
PBX can transfer calls
PBX can serve as a connection between
different office devices
Wide Area Telecommunication
Service
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WATs is a billing method for heavy users of
voice band media.
Integrated Services Digital
Network
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ISDN is a technology that uses existing
common carrier lines to simultaneously transmit
voice, video, and image data in digital form.
Network Topology
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Ring
Bus
Star
Hybrid
Hierarchical
Type of Networks
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LAN
WAN
Communication Protocol
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Open System Interconnection (OSI)
Transmission Control Protocol/Internet
Protocol (TCP/IP)
System Network Architecture (SNA)
Ethernet
X.400
X.500
SOI
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Physical layer
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Data link layer
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transmits the data from one node to another.
format the data into a record called a frame and
performs error detection.
Network layer
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causes the physical layer to transfer the frames from
node to node.
OSI
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Transport layer
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Session layer
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enable the user and host nodes to communicate with
each other.
initiate, maintains, and end each session.
Presentation layer
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formats the data so that it can be presented to the
user or the host.
OSI
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Application layer
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controls user input from the terminal and executes
the user’s application program in the host computer.
Data Transfer Modes
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Packet switching
Frame relay
Voice over frame relay
Asynchronous transfer mode (ATM)
Internet
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The internet is the world’s largest computer
network.
It is a collection of interconnected networks, all
freely exchanging information.
Internet Protocol
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The set of conventions used to pass packets
from one host to another is known as the
internet protocol (IP)
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TCP (transport control protocol is widely used.
Ways to connect to internet
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LAN
SLIP ( serial line internet protocol) or PPP
(point to point protocol)
On-line service
World Wide Web (www)
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WWW is a collection of over 30,000
independently owned computer that together as
one in an internet service.
Web Browser
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Web browser creates a unique, hypermedia
based menu on your computer screen that
provide a graphical interface to the the Web.
Hypermedia
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Connects the data on pages, allowing users to
access topics in whatever order they wish.
Allows you to bring up pictures, graphs and
other displays with sound and motion.
Web Search Engine
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Web search engines take the place of the card
catalog.
They are software programs that allow you to
search for information on the Web.
Intranet
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An intranet is an internal corporate network
built using internet and Web standards.
Cryptography
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Cryptography is the process of converting a
message into a secret code and changing the
encoded message back to regular text. (digital
signature)
Firewalls
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The most popular method of preventing
unauthorized access to corporate computer data
to construct is known as a firewall.
Firewalls can be a set of filtering rules or
specially configured hardware.
Zone
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edu = educational sites
mil = military
gov = government
net = networking organizations
nom = individuals
org = organization
com = commercial
Telnet and FTP
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Logon to another computer and access its public
files.
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Copy a file from another computer to your
computer.
E-mail (store and forward)
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To send text, binary files, sound, and images to
others.
Amplitude Shift Keying (ASK)
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To encode binary data by varying the amplitude
of signal.
Frequency Shift Keying (FSK)
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To encode binary data by varying the frequency
of signal.
Phase Shift Keying (PSK)
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To encode binary data by transition or shift
from one phase to another.
Bit Synchronization
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Coordination of signal measurement timing is
called bit synchronization.
There are two methods of bit synchronization:
Asynchronous
 Synchronous
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Asynchronous Bit
Synchronization
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Massages begin with a start bit so that the
receiving device can synchronize its internal
clock with the timing of the massage.
Asynchronous transmissions are normally short,
and the end of message is signaled by a stop bit.
Media is idle and the sender’s and receiver’s
clocks are not synchronized when no data is
being transmitted.
Synchronous Bit Synchronization
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Clocks of the sender and receiver are
synchronized by one of the following methods:
guaranteed state change
 separate clock signal
 oversampling
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Baseband & Broadband
Transmissions
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Baseband: these transmission use the entire
media bandwidth for a single channel. Most
LAN use baseband signaling.
Broadband: these transmission provide the
ability to divide the entire media bandwidth into
multiple channels.
Selecting NIC
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Type of network
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Type of media
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Token Ring, Ethernet, ATM,…etc
coaxial cable, STP, UTP, fiber,…etc
Type of bus
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ISA, EISA, VESA,…etc
Bus Architectures
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ISA (Industry Standard Architecture)
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PCI (Peripheral Computer Interconnect)
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8 bit and 16 bit bus (10MHz)
32 bit or 64 bit bus
EISA (Extended Industry Standard
Architecture)
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32 bit bus built on the ISA architecture (33 MHz)
Bus Architectures
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MCA (Micro Channel Architecture)
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32 bit bus. MCA can work in 16 or 32 bit mode.
(66MHz)
Memory Requirement
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Minimum RAM recommended for Windows
NT Server is 16 MB.
Memory Allocation
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Operating system.
Services.
Processes.
Programs.
CPU functions.
Estimating Memory
Requirement
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Minimum amount needed for Server operating
system (16 MB) plus
Number of people who will be accessing the
system at the same time plus
Average software requests per user.
Hard Disk Capacity
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Operating system files.
Software files.
Data and database files.
User files.
General public files.
Utility files.
Server management files.
Fault Tolerance
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Fault -tolerance options
disk mirroring
 disk duplexing
 redundant array of inexpensive disks (RAID)
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there are eight levels of RAID.
Disk Mirroring
Secondary
drive
Controller
server
Primary
drive
Disk Duplexing
Secondary
drive
Primary
drive
server
Controller
Project
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Set up a NIC in windows NT Server, once the
NIC operating system are installed.
Click Start button
 select Settings
 select Control Panel
 double click Network icon
 click Adapters tab
 click Add button
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Project
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Notice the list of adapters that can be install
click Cancel
 click Cancel
 close the control Panel
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Windows NT networking Models
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Workgroup.
Client-server.
Domain.
Windows NT networking Models
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Workgroup model is a decentralized networking
model.
All account administration is local to each machine.
 Each machine maintains its own account database
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Windows NT networking Models
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Client-server model is a centralized networking
model.
All administration is centralized at server.
 Clients can log on to a server via the server’s account
database and access resources associated with that
server.
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Windows NT networking Models
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NT domain model
Allows administrators to group users.
 All administration is centralized to an NT Server
that has been designated as he primary domain
controller (PDC).
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Windows NT networking Models
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In NT domain model the account database that
resides on the PDC is called Security Account
Manager (SAM)
SAM database is copied to server that has been
designated as Backup Domain Controllers
(BDC)
Each domain need al least one server
Windows NT networking Models
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PDC contains the master copy of SAM for the
entire domain and is the only server that can
make changes to the database.
If there is more than one server in a domain,
selected servers can be designated to keep a
backup copy of the SAM.
PDC’s SAM database is read-write.
Windows NT networking Models
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Domain models:
single domain
 single master domain
 multiple master domain
 complete trust domain
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Windows NT networking Models
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Criteria for choosing Domain models:
# of accounts (windows NT can support up to
40,000 account).
 The geographic scope of your domain.
 How users ant resources will be defined within the
domain.
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Domain Trust Relationship
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In situation where there are two or more
domains, users can access domains other than
their own through trust relationships set up by
the network administrator.
Each trust relationship has two parties:
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trusted domain
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granted access to resources
trusting domain
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granting the access
Example
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A n organization has a main office and ten
branches, each with its own file server and
domain. Main office domain needs access to all
branches, which is granted. Main office is
trusted domain, and branches are the trusting
domains
Trust Relationships
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One-way trust
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Two-way trust
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the trust relationship is not reciprocated. One
domain is trusted party, and the other is trusting
the trust relationship is reciprocated.
Universal trust
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two-way trust are set up among more than two
domain.
Single Domain
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Consists of a single domain.
Easy to manage.
Centralized administration.
Good for small networks.
Slow when supporting large # of accounts.
Single Domain
BDC
PDC
User
User
User
Accounts and resources
Single Master Domain
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Several domain are controlled by master domain.
All account are in the master domain.
Other domains containing only resources, such
as servers.
Single Master Domain
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All resources are located at resource domains
and can be available to all users.
Resources are decentralized.
Administrators in the resource domain have
control over their resources.
All user account are centralized in a master
domain.
Single Master Domain
Master domain
Resource
domain
Resource
domain
Resource
domain
Multiple Master Domain
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Consists of multiple single master domain
connected through two-way trust relationships.
Administration can be centralized or
decentralized.
Multiple Master Domain
Number of trusts (n) can be determined as
follow:
n=M(M-1)+(R+M)
M=# of master or accounts domains
R=# of resource domains
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Multiple Master Domain
Master
domain
Resource
domain
Master
domain
Resource
domain
Resource
domain
Complete Trust Domain
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Accounts and resources are located in each
domain.
Allows decentralized account management.
Each account can implement policies specific to
their domain.
N(N-1)=n
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where N represents # of domain
Complete Trust Domain
Account
resources
Account
resources
Account
resources
Account
resources