Advertisements
Advertisements
प्रश्न
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.
उत्तर
In the block diagram of modulator, A is Square Law Device and B is Band pass filter.
Band pass filter rejects low and high frequencies and allows a band of frequencies to pass through.
Square law device is a non linear device. It produces a non-linear output of message and carrier signals. The output from square law device is,
y(t)=Bx(t)+Cx2(t)
Where, B and C are constants and x(t)=message signal (Amsinωmt) + carrier signal (Acsinωct)
APPEARS IN
संबंधित प्रश्न
The process of superimposing a low frequency signal on a high frequency wave is_______ .
How are side bands produced?
Explain the need for modulation related to the size of antenna (aerial).
State any two types of modulation
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.
Define the term modulation. Draw a block diagram of a simple modulator for obtaining AM signal ?
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 ______.
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).
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.
