Advertisements
Advertisements
Question
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
Solution
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
RELATED QUESTIONS
The process of superimposing a low frequency signal on a high frequency wave is_______ .
Define modulation index.
What is the role of a bandpass filter?
State any two types of modulation
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.
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 ______.
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.
A 25 m long antenna is mounted on an antenna tower. The height of the antenna tower is 75 m. The wavelength (in meter) of the signal transmitted by this antenna would be ______.
A transmitting antenna has a height of 320 m and that of receiving antenna is 2000 m. The maximum distance between them for satisfactory communication in line of sight mode is 'd'. The value of 'd' is ______ km.
