Post on 02-Jun-2018
8/9/2019 Basic Telecommunication
1/12
Telecommunication
8/9/2019 Basic Telecommunication
2/12
8/9/2019 Basic Telecommunication
3/12
Simplex: A paeris a wireless telecommunications device that
receives and displays numeric or text messaes, or receivesand announces voice messaes. !ne-way paerscan only
receivemessaes,
8/9/2019 Basic Telecommunication
4/12
HA"F-#$%"&' A half-duplex(H#') system provides communication in both directions,
but only one direction at a time (not simultaneously). Typically, once a
party beins receivin a sinal, it must wait for the transmitter to stop
transmittin, before replyin (antennas are of trans-receiver type in these
devices, so as to transmit and receive the sinal as well).
An example of a half-duplex system is a two-party system such as awal*ie-tal*ie, wherein one must use +!ver+ or another previously
desinated command to indicate the end of transmission, and ensure that
only one party transmits at a time, because both parties transmit and
receive on the same freuency.
8/9/2019 Basic Telecommunication
5/12
F$"" - #$%"&' A full-duplex(F#'), or sometimes double-duplexsystem, allows
communication in both directions, and, unli*e half-duplex, allows this
to happen simultaneously. "and-line telephone networ*s are full-
duplex, since they allow both callers to spea* and be heard at the
same time, the transition from four to two wires bein achieved by a
hybrid coil. A ood analoy for a full-duplexsystem would be a two-lane road with one lane for each direction.
n full-duplex mode, data you transmit does not appear on
your screen until it has been received and sent bac* by the other
party.
8/9/2019 Basic Telecommunication
6/12
/&""$"A0 1& 2!03S
Overview
Data Rates
1G(
8/9/2019 Basic Telecommunication
7/12
/ellular networ*s: From 45 to 65
1G! "irst #e$erati$ wire%ess &e%%'%ar! ar% 1980s *$a%# tra$s+issi$, pri+ari% spee&! *M/ (*va$&e
Mbi%e $e /ste+s) a$ ters
2G! /e&$ #e$erati$ wire%ess &e%%'%ar! ate 1980s Di#ita% tra$s+issi$
ri+ari% spee& a$ %w bit-rate ata (9.6 Kbps) i#-tier! G/M, /-95 (DM*), et& w-tier (/)! w-&st, %w-pwer, %w-+bi%it e.#. */
2.5G! 2G ev%ve t +ei'+ rate (< 100bps) ata 3G! 't're 7raba$ +'%ti+eia
144 bps - 384 bps r i#-+bi%it, i# &vera#e 2 Mbps r %w-+bi%it a$ %w &vera#e
7e$ 3G! resear& i$ 4G
8/9/2019 Basic Telecommunication
8/12
OMM:;*
'b%i&/wit&ee%ep$e
;etwr(/;)
Mbi%ee%ep$e/wit&i$#
e$ter(M/)
7ase ra$s&eiver /tati$ (7Mbi%e :ser
e%% 1
e%% 2
r%ess &$$e&ti$
ire &$$e&ti$
R R
R = +e &ati$ Re#ister
R = isitr &ati$ Re#ister
8/9/2019 Basic Telecommunication
9/12
"re>'e$& Re'se
e%%s wit tesa+e $'+berave te sa+e
set re>'e$&ies
8/9/2019 Basic Telecommunication
10/12
8/9/2019 Basic Telecommunication
11/12
8/9/2019 Basic Telecommunication
12/12
Freuency Spectrum
Focus !n:
HF 7 Hih Freuency(3-30MHz
) 8HF 7 8ery Hih Freuency (30-300 MHz)
$HF 7 $ltra Hih Freuency (300MHz - 3 GHZ)
"ower 9icrowave Freuencies