Advertisements
Advertisements
प्रश्न
What is the role of a bandpass filter?
Advertisements
उत्तर
The bandpass filter blocks the signal which is d.c. or has frequencies ω, 2ωc and 2ωm and allows a particular band of the frequency signal to pass.
APPEARS IN
संबंधित प्रश्न
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?
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%
State any two types of modulation
The carrier wave is represented by
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 100 m long antenna is mounted on a 500 m tall building. The complex can become a transmission tower for waves with λ.
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.
