preview

Advantages And Disadvantages Of Frequency Modulation

Decent Essays
ANGLE MODULATION
Chapter Objectives
This chapter will help you to:
1. Define and explain the processes of frequency modulation (FM) and phase modulation (PM) and state their differences.
2. Calculate the modulation index given the maximum deviation and maximum modulating frequency, determine the significant number of sidebands in an FM signal, and calculate the bandwidth of an FM signal.
3. Define pre-emphasis and de-emphasis, state their benefits, and show how they are accomplished.
4. Name the advantages and disadvantages of FM and PM compared to AM.

Angle modulation is a technique in which the angle of the carrier wave is varied according to the instantaneous amplitude of the modulating signal. There are two types of angle modulation.
1. Frequency Modulation
2. Phase Modulation
Frequency Modulation: (Definition & Introduction)
FM is a technique in which the instantaneous frequency of the carrier wave is varied according to the instantaneous amplitude of the modulating signal. In other words if the amplitude of the modulating signal increases, then there will be a corresponding increase in the frequency of the modulated wave, similarly if the amplitude of the modulating signal decreases, then there will be a corresponding
…show more content…
As can be seen in Figure 3.1 (a) the modulating signal increases from its negative peak value during this quarter, and at time t3 it becomes zero. This sinusoidal increase in the amplitude of the modulating signal is mapped on to the carrier signal by increasing its frequency. At time T3, the amplitude of the modulating signal is zero and hence there will not be any deviation in the carrier frequency from its original value. Thus between time T2 and T3, the frequency of the modulated carrier increases from its minimum value attained at time t2. This is shown in Figure 3.l(c) by inserting more cycles during quarter III as compared to the number of cycles that occurred during the quarter
Get Access