Skip to main content

300x250 Ads

Analog modulation

By Ashik

Modulating signal and carrier Wave

 

Modulated wave



 
Frequency spectrum of AM wave

 
If the equation of modulating signal is




And the carrier wave equation is




Then the modulated wave is the superposition of the above two waves.




 












 
Amplitude of the modulated wave is


 
Instantaneous voltage of the Amplitude modulated wave is


 
Expand the above equation using trigonometrically relation

 
The first term represent the nu-modulated carrier.
Second and third terms represent the additional sidebands.





Representation of AM wave




  















 
Modulation index





Power relation in the AM wave



 
Total power in the modulated wave  


Carrier power


 
Similarly 




 
We have from above relations



 
Maximum power in AM wave
 
For m=1
 means 100% modulation


 
Current Calculation:
 
It is the modulated current and Ic is the nu-modulated current and R is the radiation resistance of the antenna. 






Download the ppt file

Labels:

Comments

Post a Comment

Popular posts from this blog

Armature Winding ,Pole Pitch, Coil Span, Commutator Pitch

By Ashik
Now we are going to discuss about armature winding in details. Before going through this section, we should understand some basic terms related to armature winding of dc generator . Pole Pitch Definition of Pole Pitch The pole pitch is defined as peripheral distance between center of two adjacent poles in dc machine. This distance is measured in term of armature slots or armature conductor come between two adjacent pole centers. This is naturally equal to the total number of armature slots divided by number of poles in the machine. If there are 96 slots on the armature periphery and 4 numbers of poles in the machine, the numbers of armature slots come between two adjacent poles centers would be 96/4 = 24. Hence, the pole pitch of that dc machine would be 24. As it is seen that, pole pitch is equal to total numbers of armature slots divided by total numbers of poles, this can alternatively referred as armature slots per pole . Coil Span or Coil Pitch Coil of
Post a Comment
Read more

Propagation-Radio-Waves

By Ashik
Radio Wave Propagation types
Post a Comment
Read more

Coding

By Ashik
Binary Coding 1. Binary Coded Decimal (BCD) Binary coded decimal (BCD) is a way to express each of the decimal digits with a binary code. There are only ten code groups in the BCD system, so it is very easy to convert between decimal and BCD. Because welike to read and write in decimal, the BCD code provides an excellent interface to binary systems. Examples of such interfaces are keypad inputs and digital readouts. The 8421 Code: The 8421 code is a type of BCD (binary coded decimal) code. Binary coded decimal means that each decimal digit, 0 through 9, is represented by a binary code of four bits. The designation 8421indicates the binary weights of the four bits 2 3 , 2 2 , 2 1 , 2 0 . The ease  of conversion between 8421 code numbers and the familiar decimal numbers is the main advantage of this code.  All wehave to remember are the ten binary combinations that represent the ten decimal digits as shown in Table 1. The 8421 code is the predominant BCD code, and when we ref
Post a Comment
Read more

Add