ANALOG AND DIGITAL SIGNALSSUBJECT : ELECTRONIC COMMUNICATION

ANALOG & DIGITAL SIGNALS

• Review the definitions of analog and digital signals.

• Detail the working of an analog and digital signals.

• Examples of Analog.

• Analog Transmission

• Pros and Cons of Analog.

• Examples of Digital.

• Digital Transmission.

ANALOG & DIGITAL SIGNALS

• Pros and Cons of Digital.

• Applications.

DEFINITION:

ANALOG SIGNALS• A signal whose amplitude can take any value in continuous (infinite) range is an analog signal.

• More exact values, but more difficult to work with

DIGITAL SIGNALS

• A signal whose value can take only a finite number values is a digital signal.

• Not as exact as analog, but easier to work with

Example: A digital thermostat in a room displays a temperature of 72. An analog thermometer measures the room temperature at 72.482. The analog value is continuous and more accurate, but the digital value is more than adequate for the application and significantly easier to process electronically.

4 DIFFERENT THINGS : ANALOG, DIGITAL, CONTINUOUS AND DISCRETE• As discussed on previous slide being digital or analog is a

matter of amplitude domain where being continuous and discrete is a matter of time domain.

DIFFERENCE IN WORKING:

• The working of the digital signals are more reliable and accurate because they use the digital media or the numeric method where as analog signals are based on the small fluctuations.

• Digital signals are used to play that information which is came from re-sampling, whereas analog are known for playing recorded data.

• Digital signals have priority over analog signals because with the help of digital signals users have ability to change the visual and the audio or re-record it but with analog signals you can do such parameters.

EXAMPLE OF ANALOG SIGNALS:• Important property of the analog signals is they are continuous on

both time and amplitude domain.

• They can be periodic (repeating) or non-periodic.

• Sine waves are common analog signals.

• Note that this square wave is not a digital signal because its minimum value is negative.

• Analog signals are easy to understand as they are “real” signals i.e. the most of the signals naturally exists are Analog. E.g. temperature of atmosphere, intensity of light, intensity of voice etc.

0 volts

Sine Wave Sawtooth Wave(not digital)

Random-Periodic

ANALOG TRANSMISSION:

• Transmit analog signals without regard to content.

• Attenuation limits length of transmission link

• Cascaded amplifiers boost signals energy for longer distances but cause distortion

• Analog data can tolerate distortion.

• Introduces errors in digital data.

PROS AND CONS OF ANALOG SIGNALS:• Advantages:

• major advantages of the analog signal is infinite amount of data.

• Density is much higher.

• easy processing.

• Disadvantages:

• Unwanted noise in recording.

• If we transmit data at long distance then unwanted disturbance is there.

• Generation loss is also a big con of analog signals.

EXAMPLE OF DIGITAL SIGNALS:• Digital Signals are quantized on amplitude domain hence they can have

only some specific values.

• Digital signal are commonly referred to as square waves or clock signals.

• The time the signal is high (tH) can vary anywhere from 1% of the period to

99% of the period.

• Text and Integers.

DIGITAL TRANSMISSION:

• Concerned with the content of the signal.

• Attenuation endangers integrity of data.

• Digital signal

• Repeaters achieve greater distance.

• Repeaters recover the signal and retransmit.

PROS AND CONS OF DIGITAL SIGNALS:• Advantages:

• Because of their digital nature they can travel faster in over digital lines.

• Ability to transfer more data as compared to analog.

• Disadvantages:

• Greater bandwidth is essential.

• Systems and processing is more complex.

APPLICATIONS:• Analog

Thermometer.

photocopiers

old land-line telephones

audio tapes

VCRs (same as TV)

• Digital:

PCs, PDAs

Mobile Phones

Signal Processing

Encoding

New generation communication

PRESENTATION BY…

• Arjun Dedaniya (130170111016)

• Asif Faruki (130170111020)

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NO MAN REALLY BECOMES A FOOL UNTIL HE STOPS ASKING QUESTIONS.

- CHARLES P. STEINMETZ

Thank You!