Amplitude shift keying (ASK) is a form of amplitude modulation that represents digital data as variations in the amplitude of a carrier wave. It imparts discrete amplitude levels to a sinusoidal carrier signal. ASK can be binary, using two amplitude levels, or multilevel using more than two levels. The modulation is performed by band-limiting the signal to round off sharp discontinuities before transmission. Demodulation recovers the band-limited bit stream and regenerates the binary bit stream. ASK is commonly used to transmit digital data over optical fiber and transmit Morse code using LED transmitters.
2. A form of amplitude modulation process.
Represents digital data as variations in the amplitude of a carrier wave.
Imparts to a sinusoid, two or more discrete amplitude levels.
Uses a finite number of amplitudes, each assigned a unique pattern
of binary digits.
What is Amplitude Shift Keying ?
4. ASK GENERATION AND MODULATION
From a sinusoidal wave signal, ASK output is generated by BAND LIMITING method.
By applying BAND LIMITING method, sharp discontinuities would be rounded-off,
before transmission.
6. Amplitude Shift Keying is of Two types-
1. Binary ASK
2. Multilevel ASK
Binary ASK is implemented using only 2 levels.
It is known as ON-OFF keying.
Multilevel ASK is implemented with more than two level.
Different Amplitude used are – 4,8,16…
Different Bits used are- 2,3,4…
TYPES OF AMPLITUDE SHIFT KEYING
12. FDM
Sharing is done by assigning each user a specific
frequency (Carrier Frequency)
Modulation equipment is used to move each
signal to the required frequency band.
Multiplexing equipment is needed to combine
the modulated signal
13. FDM
Separation of spectrum into smaller frequency
bands
Channel gets band of the spectrum for the whole
time
21. Introduction
• Twisted pair is the simples, oldest and low priced cable
medium.
• It is made up of two insulated copper wires, typically, twisted
around each other in a continuous spiral.
• The purpose of twisting the wires is to reduce electrical
interference (or noise) from similar pairs close by.
Unshielded Twisted Pair (UTP) Cable
– Shielded Twisted Pair (STP) Cable
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23. Unshielded Twisted Pair (UTP) Cable
• Unshielded Twisted Pair (UTP) is the most common type of twisted
pair cable used in telecommunication networks.
• The reason for placing twist in the pair of wires is to minimize the
vulnerability of the twisted pair cable to external electrical noise.
• Its frequency range is suitable for data transmission as well as voice
transmission (100 Hz-5 MHz).
•
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26. Advantages
• The advantages of UTP are its low cost,
• It is easy to installation procedure.
• It is basically used in LAN implementations.
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28. Shielded Twisted Pair (STP) Cable
• In Shielded Twisted Pair cable, each pair of
insulated conductors is encased in a metal shield
to prevent Crosstalk.
• The quality aspect of shielded twisted pair is
same as the unshielded twisted pair but the
shield must be connected to ground.
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31. Uses
• STP cables use same connectors as UTP, and are
more expensive than UTP cable.
• It is used for both analog and digital
transmission.
• It is said to be a “balanced transmission medium
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