Table of Contents
What happens to the signal when the modulation index goes above 1?
When the value of the modulation index goes more than one then it causes overmodulation which leads to distortion and causes the bandwidth to not be preserved. The modulation index is the amount of modulation that is done on a carrier signal.
What is the effect of modulation index in FM?
As the modulation index increases for frequency modulation (FM), the number of significant sidebands increases, but the sidebands’ total average power remains constant.
Which type of modulation has modulation index is equal to 1?
Frequency modulation can be classified as narrowband if the change in the carrier frequency is about the same as the signal frequency, or as wideband if the change in the carrier frequency is much higher (modulation index > 1) than the signal frequency.
Why is modulation index kept less than 1?
Modulation index is defined as a measure of the extent of modulation done on a carrier signal wave. Its value is generally kept less than 1 for practical purposes to avoid over modulation which leads to distortions in the modulated signal and then makes it very hard to demodulate and extract the modulating signal.
How power of the FM signal is affected by the change in modulation index?
Frequency modulation (FM) In frequency modulation, the frequency rather than the amplitude of the carrier wave is made to vary in proportion to the varying amplitude of the modulating signal, as shown in Fig. Also in AM if the amplitude of modulation is to be increased, the power must be increased proportionately.
What is the effect of the modulation index on the bandwidth of FM signal?
Increasing modulating frequency increases the frequency separation between sidebands. Increasing modulating frequency for a given level of deviation reduces modulation index. As a result, it reduces the number of sidebands with significant amplitude. This has the result of reducing the bandwidth.
What is the modulation index of FM wave?
Difference between Amplitude Modulation and Frequency Modulation
| Amplitude Modulation | Frequency Modulation |
|---|---|
| The AM frequency ranges from 535 kHz – 1705 kHz | The FM frequency ranges from 88 MHz – 108 MHz in the higher spectrum |
| The modulation index of AM ranges from 0 to 1 | The modulation index of FM is higher than 1 |
What will happen if the modulation index of an AM radio station is increased?
If AM radio station increases its modulation index then there is an increase in receiving RF signal. Explanation: Modulation index tells us the amount by which the carrier wave is varied with respect to the message signal. Increase in it also increase the ability of increase reception of RF signals.
What will happen if modulation index is greater than 100\%?
When the modulation index is greater than 100 \%, the message intended to be transferred will not be communicated properly. The over modulation of signal damages the signal and deteriorates the signal strength and quality.
What does modulation index indicate?
Definition of modulation index : a measure of the degree of frequency modulation expressed numerically for a pure tone modulation as the ratio of the frequency deviation to the frequency of the modulating signal.