Advertisements
Advertisements
प्रश्न
Define the term modulation. Draw a block diagram of a simple modulator for obtaining AM signal ?
Advertisements
उत्तर
Modulation is the process in which low frequency message signal is superimposed on high frequency carrier wave so that they can be transmitted over long distances.
The block diagram for a simple modulator for obtaining AM signal is shown below:
संबंधित प्रश्न
A carrier wave of peak voltage 15 V is used to transmit a message signal. Find the peak voltage of the modulating signal in order to have a modulation index of 60%
In a communication system, what is meant by modulation?
The carrier wave is represented by
The carrier wave of a signal is given by C(t) = 3 sin (8πt) volt. The modulating signal is a square wave as shown. Find its modulation index.
In the block diagram of a simple modulator for obtaining an AM signal, shown in the figure, identify the boxes A and B. Write their function.
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 ?
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 ______.
I-V characteristics of four devices are shown in Figures.
 |
 |
 |
|
| (i) | (ii) | (iii) | (iv) |
Identify devices that can be used for modulation.
A male voice after modulation-transmission sounds like that of a female to the receiver. The problem is due to ______.
An audio signal of 15kHz frequency cannot be transmitted over long distances without modulation because ______.
- the size of the required antenna would be at least 5 km which is not convenient.
- the audio signal can not be transmitted through sky waves.
- the size of the required antenna would be at least 20 km, which is not convenient.
- effective power transmitted would be very low, if the size of the antenna is less than 5 km.
