Modulation is the process of altering a carrier signal to transmit information, which is vital for sending audio signals over distances. It can be categorized into analog and digital modulation techniques, with various methods such as amplitude modulation (AM), frequency modulation (FM), and pulse code modulation (PCM). Digital modulation techniques include amplitude shift keying (ASK), frequency shift keying (FSK), and phase shift keying (PSK), each using distinct approaches to represent data through variations in signals.

1. MODULATION
Analog,digital&pulse

2. What is modulation…???
Modulation isthe processofaltering acarriersignaltotransmitinformation.
Modulationisthebasicrequirementfortransmittingthemessage signalthroughfree
space.
Itistheprocessof transmissionofinformationsignal(lowfrequency audiosignal)
usingahighfrequencycarriersignal.
Modulation =Addinginformationto acarriersignal.

3. MODULATION
Analog
Modulation
Digital
Modulation

4. •
NALOGMODULATION &DIGITALMODULATION
•ANALOG SIGNAL have continuous electrical signals, while digital signals have
non-continuous electrical signals.

6. Pulse modulation
• Itisananalogmodulatingschemeinwhichthedurationorwidthortimeofthe pulse
carriervaries proportionaltotheinstantaneous amplitudeof themessagesignal.
• Thewidthofthepulse variesinthismethod, butthe amplitudeof thesignalremains
constant.
• Amplitudelimiters areusedto maketheamplitude ofthe signalconstant.These
circuitsclipoff theamplitude,to adesiredlevel andhencethe noise islimited.

7. Analog
Modulation
Frequency
modulation(FM)
Amplitude
modulation(AM)
Phase
modulation(PM)

8. TYPES OF ANALOG MODULATION
• Amplitudemodulation(AM): Theheight(i.e., thestrengthorintensity)ofthesignalcarrierisvariedto
representthedatabeingaddedtothesignal.
• Frequencymodulation(FM): Thefrequencyofthecarrierwaveformisvariedtoreflectthefrequency
ofthedata.
• Phasemodulation(PM): Thephaseof thecarrierwaveformisvariedtoreflectchangesinthe
frequencyofthedata.InPM,thefrequencyisunchanged whilethephaseischangedrelativetothe
basecarrierfrequency.ItissimilartoFM.

9. Modulation
methods
Frequency shift
keying (FSK)
Amplitude
shift keying (ASK)
Phase shift
keying (PSK)

10. • ASK (AmplitudeShift Keying)
Adigitalmodulationmethodthatsendstransmission databyvaryingthe presence/absence of
analogsignals.
• FSK (Frequency ShiftKeying)
Thistechniqueutilizesthe difference intheamplitudeofanalogsignals tomodulate digital
signalsbyswitchingbetween lowfrequency andhighfrequency inordertorepresent 0and1.
• PSK (PhaseShift Keying) isthedigitalmodulationtechniqueinwhichthephaseofthe carrier
signalischangedbyvaryingthesineandcosineinputsataparticulartime.PSK techniqueis
widely usedforwireless LANs, bio-metric, contactless operations, alongwithRFID and
Bluetooth communications.

12. PSK

13. PCM
• Stands for pulse code modulation
• Rather than transmitting the sampled values itself we may
represent each quantization level by a code no. & transmit the
code no. which is converted into binary equivalent before
transmission.
• Then these digits of the binary representation of the code are
transmitted in the form of pulses.

16. -BY
-ABHISHEK YADAV
-ALISHA BATHAM
-ANAMIKA RAJPUT