21-01-2013, 03:54 PM
Analog– Communication
[attachment=47909]
Define modulation?
Modulation is a process by which some characteristics of high frequency carrier signal is varied in accordance with the instantaneous value of the modulating signal.
2.What are the types of analog modulation? Amplitude modulation.
Angle Modulation
1. Frequency modulation
2. Phase modulation.
3.Define depth of modulation.
It is defined as the ratio between message amplitude to that of carrier amplitude. m=Em/Ec
4. What are the degrees of modulation? Under modulation. m<1 Critical modulation m=1
Over modulation m>1 5.What is the need for modulation?
Needs for modulation:
Ease of transmission Multiplexing
Reduced noise
Narrow bandwidth
Frequency assignment
Reduce the equipments limitations.
6.What are the types of AM modulators?
There are two types of AM modulators. They are
Linear modulators
Non-linear modulators
Linear modulators are classified as follows
Transistor modulator
There are three types of transistor modulator.
₃ Collector modulator ₃ Emitter modulator ₃ Base modulator
Switching modulators
Non-linear modulators are classified as follows
Square law modulator Product modulator
Balanced modulator
7.Give the classification of modulation.
There are two types of modulation. They are
Analog modulation Digital modulation
Analog modulation is classified as follows
Continuous wave modulation Pulse modulation
Continuous wave modulation is classified as follows
Amplitude modulation
₃ Double side band suppressed carrier ₃ Single side band suppressed carrier ₃ Vestigial side band suppressed carrier
Angle modulation
₃ Frequency modulation ₃ Phase modulation
Pulse modulation is classified as follows
Pulse amplitude modulation Pulse position modulation Pulse duration modulation Pulse code modulation
Digital modulation is classified as follows
Amplitude shift keying Phase shift keying
Frequency shift keying
8.What is single tone and multi tone modulation?
If modulation is performed for a message signal with more than one frequency component then the modulation is called multi tone modulation.
If modulation is performed for a message signal with one frequency component then the modulation is called single tone modulation.
9 .The antenna current of an AM transmitter is 8A when only carrier is sent. It increases to 8.93A when the carrier is modulated by a single sine wave. Find the percentage modulation.
[attachment=47909]
Define modulation?
Modulation is a process by which some characteristics of high frequency carrier signal is varied in accordance with the instantaneous value of the modulating signal.
2.What are the types of analog modulation? Amplitude modulation.
Angle Modulation
1. Frequency modulation
2. Phase modulation.
3.Define depth of modulation.
It is defined as the ratio between message amplitude to that of carrier amplitude. m=Em/Ec
4. What are the degrees of modulation? Under modulation. m<1 Critical modulation m=1
Over modulation m>1 5.What is the need for modulation?
Needs for modulation:
Ease of transmission Multiplexing
Reduced noise
Narrow bandwidth
Frequency assignment
Reduce the equipments limitations.
6.What are the types of AM modulators?
There are two types of AM modulators. They are
Linear modulators
Non-linear modulators
Linear modulators are classified as follows
Transistor modulator
There are three types of transistor modulator.
₃ Collector modulator ₃ Emitter modulator ₃ Base modulator
Switching modulators
Non-linear modulators are classified as follows
Square law modulator Product modulator
Balanced modulator
7.Give the classification of modulation.
There are two types of modulation. They are
Analog modulation Digital modulation
Analog modulation is classified as follows
Continuous wave modulation Pulse modulation
Continuous wave modulation is classified as follows
Amplitude modulation
₃ Double side band suppressed carrier ₃ Single side band suppressed carrier ₃ Vestigial side band suppressed carrier
Angle modulation
₃ Frequency modulation ₃ Phase modulation
Pulse modulation is classified as follows
Pulse amplitude modulation Pulse position modulation Pulse duration modulation Pulse code modulation
Digital modulation is classified as follows
Amplitude shift keying Phase shift keying
Frequency shift keying
8.What is single tone and multi tone modulation?
If modulation is performed for a message signal with more than one frequency component then the modulation is called multi tone modulation.
If modulation is performed for a message signal with one frequency component then the modulation is called single tone modulation.
9 .The antenna current of an AM transmitter is 8A when only carrier is sent. It increases to 8.93A when the carrier is modulated by a single sine wave. Find the percentage modulation.