This presentation is about digital signals with reference to the electromagnetic spectrum.

2. CONTENTS
1. A description of how the technology works, with reference
to the electromagnetic spectrum.
2. How this technology changed over time?
3. The negative and positive impact of this technology on
society

3. A DESCRIPTION OF HOW DIGITAL SIGNALS WORKS
Signals are waves which carry information. Radio waves,
microwaves, infrared and visible light are used as signal
carriers (refer to Fig.2).
Digital signal (shown in Fig.1) is one of the two types of signals.
It consists of a chains of on and off pulses, which are coded
using the binary number system; that is 1 for on and 0 for off.
Time division multiplexing (TDM) is the technique used to
transmit this signal. It starts off by breaking down the data into
smaller amounts and then merged with an electromagnetic
wave, known as the carrier wave, to be transferred under a
single frequency. The information is obtained by the removal of
the carrier wave and the signal is restored.
Digital transmission is as the data over channels to a single
point, as target (point-to-point) or a multipoint target (point-to-
multipoint). Copper wires, optic fibers, wireless communication
channels, storage media and computer buses are the variety of
channels used.
Fig.1.This is a synchronized waveform
of digital signal called clock signal.
KEY:
low voltage
high voltage
Raising edge: low-high voltage increase
Failing edge: high-low voltage decrease

4. Fig.2.Carrier waves are used to transport the signal to places. Radio waves
microwaves, infrared and visible light are used during that process.

5. HOW THIS TECHNOLOGY CHANGED OVER TIME?
Digital signals have transformed how we watch TV to
how we make phone calls from our mobile without
wires like the landline. It is the, so called, new
generation signal compared to analog signal. Analog
signal is also a type of signal. It changes its amplitude
and frequency constantly, unlike the digital signal
which can only go on (1) or off (0). Digital signals can
maintain the quality of the data they contain over long
distance. Transitions, using digital signal, is simpler as
the binary number system is easily read by
computers.
In our world today we use both, analog and digital
signal transmissions, at the same time. An example of
this would be recording equipment and microphones
(Fig.3). Television (Fig.4) and radio broadcasters are
changing from analog to digital transmissions not only
because of the quality, but also as it could carry more
data per second, than analog can.
Fig.4. These
are the
reasons why
analog is
replaced by
digital
when it comes
to
broadcasting.

6. Fig.3.
This diagram shows how digital and analog signals are incorporated
microphones.
ADC: Analog-to-Digital Converter DAC: Digital-to-Analog Converter

7. POSITIVE NEGATIVE
Good quality even for long distance
transmissions and high quality
imaging and audio (TV and Mobile
phones)
• Even if there is interference
through the transmission
process, the signal is
regereated to its original data.
More data, per second, compared to
analog signal.
• As the data is broken up to be
quickly transferred thus more
data could be crammed in.
Digital cellular phones are good
quality to converse without a cord
restricting you from moving around.
• This is developed as digital
signal could be transferred
This data (signal) could easily be
hacked
• It is easy to decode digital
because of the two digit
binary number system used
for coding.
More expensive than analog, as it is
incorporated with the latest
technology.
• It is to makes the latest
phones and technology more
luxurious, thus more people
will buy it.
Analog signal still has a richer voice
quality than digital.
• As it is the original wave
getting transferred without
any alteration.
THE NEGATIVE AND POSITIVE IMPACT OF THIS
TECHNOLOGY ON SOCIETY

8. By: NandithaMN

9. BIBLIOGRAPHY
• https://en.wikipedia.org/wiki/Data_transmission
• https://in.answers.yahoo.com/question/index?qid=201503050837
10AAPjb8E
• https://learn.sparkfun.com/tutorials/analog-vs-digital
• http://ocw.mit.edu/courses/electrical-engineering-and-computer-
science/6-450-principles-of-digital-communications-i-fall-
2006/lecture-notes/book_1.pdf
• http://telecom.hellodirect.com/docs/Tutorials/AnalogVsDigital.1.05
1501.asp
• https://www.youtube.com/watch?v=XCu6L4kQF3k
• http://electronics.howstuffworks.com/digital-versus-analog1.htm