The document covers the concept of angle modulation, focusing on definitions of phase modulation (PM) and frequency modulation (FM), along with their relationship and applications in various communication technologies such as radio broadcasting and cellular communication. It outlines how the phase angle of the carrier wave varies according to the modulating signal while keeping amplitude constant. Additionally, it discusses the mathematical representation and implications of frequency deviation in FM and PM.

1. ANGLE MODULATION
DIKSHA PRAKASH

2. TOPICS COVERED
• Introduction
• Concept of Angle Modulation : Basic Definition
– Phase Modulation (PM) Definition
– Frequency Modulation (FM) Definition
• Frequency Deviation
• Relationship between Phase Modulation (PM)
and Frequency Modulation (FM)
• Single Tone Frequency Modulation
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3. INTRODUCTION
• Frequency or phase of message signal is
varied according to the message signal.
• The amplitude is kept constant.
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4. Concept of Angle Modulation :
Basic Definition
DEFINITION
Total phase angle of the carrier wave is
varied according to the instantaneous
value of the modulating signal keeping the
amplitude constant.
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5. TYPES OF ANGLE
MODULATION
• Depending upon the ways in which we can
vary phase angle ‘Ǿ’, the types are:
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6. APPLICATIONS OF ANGLE
MODULATION
• Radio Broadcasting
• Two way mobile radio
• Microwave communication
• TV sound transmission
• Cellular radio
• Satellite communication
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7. ADVANTAGES AND
DISADVANTAGES
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8. PHASE MODULATION
Phase angle Ǿ is varied in accordance to
baseband or modulating signal.
The mathematical representation of the
same can be shown as:
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9. DIKSHA PRAKASH

10. DIKSHA PRAKASH

11. FREQUENCY MODULATION
• It is a type of angle modulation in which
the instantaneous frequency varied
linearly in accordance to baseband or
modulating signal.
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12. FREQUENCY MODULATION
Negative
Deviation
Positive
Deviation
FIGURE: Illustration of Frequency Deviation
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13. Frequency Relationship between
PM and FM
Expression for PM wave is:
Expression for FM wave is:
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14. • In PM, the phase angle varies linearly with
base band signal x(t).
• In FM, the phase angle varies linearly with
the integral of baseband signal x(t).
Thus, FM can be obtained from FM and
the converse is also true.
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15. FM using PM
FM signalAn
Integrator
Phase
Modulator
Carrier
Generator
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16. PM using FM
A
Differentiator
Frequency
Modulator
Carrier
Generator
PM Signal
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17. SINGLE TONE FREQUENCY
MODULATION
• General expression for FM wave:
Equation shows non-linear modulation
process.
Hence to avoid complexity, we use single
tone frequency modulation.
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18. DIKSHA PRAKASH

19. INFERENCES
• Frequency of carrier wave is varied
according to x(t).
• Maximum amplitude of the carrier wave is
kept constant.
•
• This deviation is called ‘Frequency
Deviation’
• Amount of deviation depends upon
amplitude of x(t)DIKSHA PRAKASH

20. • For FM, the modulation index is denoted
by:
or,
The modulation index maybe greater than
unity.
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21. MATHEMATICAL EXPRESSION
& NUMERICALS
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