Advertisements
Advertisements
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%
Advertisements
उत्तर
The amplitude of the carrier wave, Ac = 15 V
Modulation index, m = 60% = 0.60
Amplitude of the modulating wave = Am
Using the relation for modulation index:
`m = A_m/A_c`
`:. A_m = mA_c`
`= 0.60 xx 15 = 9 V`
APPEARS IN
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.
Why is Modulation index kept low?
In a communication system, what is meant by modulation?
In the given block diagram of a receiver, identify the boxes labeled as X and Y and write their functions.
Answer the following question.
Why a signal transmitted from a TV tower cannot be received beyond a certain distance? Write the expression for the optimum separation between the receiving and the transmitting antenna.
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 ______.
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.
A TV transmission tower antenna is at a height of 20 m. How much service area can it cover if the receiving antenna is (i) at ground level, (ii) at a height of 25 m? Calculate the percentage increase in area covered in case (ii) relative to case (i).
