Telecommunications – A Level Physics
A description of telecommunications: AM and FM; use of carrier waves; analog and digital signals; broadcast options; satellite transmission; gain and attenuation; PSTN; mobile/cell phones and networks.
Telecommunications – A Level Physics
Telecommunications – A Level Physics
A description of telecommunications: AM and FM; use of carrier waves; analog and digital signals; broadcast options; satellite transmission; gain and attenuation; PSTN; mobile/cell phones and networks.
One way of doing it is Frequency Division Multiple Access (FDMA) : FDMA
separates the spectrum into distinct voice channels by splitting it into
uniform chunks of bandwidth. Each call sends its signal at a different
frequency within the available band per geographical cell. But there are
other ways with digital communications. Wikieducator has a good pdf piece
on cell phone technology.
thanks very much, after watching your your videos I realize that physics is
not difficult to understand if you are taught properly. I learned more
physics from your videos in two days than may be in two years in school.
Its very exciting.
THANK YOU VERY VERY VERY VERY MUCH , I WILL NEVER FORGET THIS KINDNESS
PLEASE KEEP THE VIDEOS COMING . HAVE A NICE DAY SIR
Thank you very much sir, you are a-w-e-s-o-m-e 🙂
sorry but.. a coil will flow!! LOL 😀
please tell me from where the carrier waves are transmitted??from a radio
station?and how does the information signal attatch on the radio carrier
waves??and the informaton signal refers to the sound waves??
All the relevant waves are electromagnetic waves. Sound waves are
converted. Carrier waves are generated either in the phone or the
transmitter (depending on which way the information is flowing). The
carrier wave is an EM wave which has the characteristic of being able to
travel sufficient distances (usually in the microwave region). The sound
wave which is converted to an EM wave is then embedded in the carrier wave.
Once it reaches its destination the carrier wave is stripped off.
Thank you SO SO SO much!!!
If you embed a signal within a carrier wave then there is a degree of
uncertainty about the precise wavelength of the carrier wave. That
uncertainty is really the bandwidth. It is the amount of the spectrum that
is taken up to cover all the frequencies needed to be included in the
signal such that there will be no interference with the signal embedded in
a neighbouring carrier away
Is it really how ADC works? I mean to represent a wave with a certain
amplitude in analog, it takes several waves to represent the same wave in
digital… Which is the reason “you loose information density by converting
from analog to digital”… Or am I missing something? I am referring to
16:50
Thank you Sir for the wonderful you tube. please give me detail explanation
how is Microwave auditory effect this is what I mean microwave hearing, is
modulated using satellite.
very nicly put….i second the comment above…god bless u
Great video, thank you! What do you mean when you talk about the bandwidth
of the AM wave because you say that the amplitude is 20kHz but I thought
amplitude was measured as a distance?
In an AM wave the carrier waves sine wave is itself modulated to carry the
signal. The bandwidth is the degree of spread on the carrier wave.
First of all thank you sir for this wonderful explanation of
Telecommunication
I have one doubt here that if you are telling that for sending message to
far distance we have to modulate it at higher Frequency But On the other
hand FM (Which operates at higher frequency) travels less distance as
compared with AM (Which operates at lower frequency) Why is it so can you
please clarify that???
Very nice video covering a lot of good information. I detail: the AM
modulation you are drawing is not quite like that in normal AM, what you
have drawn is side band modulation where no effect is transmitted when the
modulation signal is 0 v. With normal AM, the carrier voltage is half its
max when modulation signal is at 0 V.
Sir, during your explanation of bandwidth, why did you use kilohertz as the
unit of amplitude?
thanks :)
that was so helpful, thank you 🙂 
+Bishoy George +Mohamed Yasser 
Coil will flow! xD xD hahahahahha xD xD
Thank you very much i have physix=cs exam tomorrow and i think i doing it
well!!!!!
thank you very much.
Is the carrier-wave digitalized too (before transmission)? And how does a
digital signal move the electrons in the antenna (to create the
EM-radiation)?