Advertisements
Advertisements
प्रश्न
Given modulation index physical significance .For an amplitude modulated wave, the maximum amplitude is found to be 10 V while the minimum amplitude is 2 V. Determine the modulation index μ ?
Advertisements
उत्तर
Physical significance of modulation Index.
To determine the strength and quality of transmitted signal. If the modulation index is small, the amount of variation in the carrier amplitude is small. Thus, the audio signal transmitted will not be strong. The greater the degree of modulation, the stronger and clearer will be the audio signal during reception.
Maximum amplitude, Amax = 10 V
Minimum amplitude, Amin = 3 V
Thus modulating index `mu =(A_(max) -A_(min))/(A_(max) +A_(min)) = (10+3)/(10 -3) = 13/7 = 1.85`
संबंधित प्रश्न
How are side bands produced?
The carrier wave is given by
C(t) = 2sin(8πt) volt.
The modulating signal is a square wave as shown. Find modulation index.
A carrier wave of peak voltage 12 V is used to transmit a message signal. What should be the peak voltage of the modulating signal in order to have a modulation index of 75%?
Due to economic reasons, only the upper sideband of an AM wave is transmitted, but at the receiving station, there is a facility for generating the carrier. Show that if a device is available which can multiply two signals, then it is possible to recover the modulating signal at the receiver station.
Explain the need for modulation related to the size of antenna (aerial).
Why is Modulation index kept low?
What is the role of a bandpass filter?
A 20 volt AC is applied to a circuit consisting of a resistance and a coil with negligible resistance. If the voltage across the resistance is 12 volt, the voltage across the coil is ______.
Broadcasting antennas are generally ______.
I-V characteristics of four devices are shown in Figures.
 |
 |
 |
|
| (i) | (ii) | (iii) | (iv) |
Identify devices that can be used for modulation.
