Name the type of waves which are used for line of sight (LOS) communication. What is the range of their frequencies?
A transmitting antenna at the top of a tower has a height of 20 m and the height of the receiving antenna is 45 m. Calculate the maximum distance between them for satisfactory communication in LOS mode. (Radius of the Earth = 6.4 × 106 m)
Types of waves are:
i) space waves
ii) radio waves
iii) microwave
The frequency range for LOS communication is 40 MHz.
Given,
Height of the transmitting antenna, h = 20 m
Height of receiving antenna = 45 m
So, the maximum distance between transmitting antenna and receiving antenna is given by,
The decimal equivalent of the binary number (11010.101)2 is
9.625
25.265
26.625
26.265
C.
26.625
The decimal equivalent can be found as follows,
(11010.101)2 = 0 × 20 + 1 × 21 + 0 × 22 + 1 × 23 + 1 × 24 + 1 × 2-1 + 0 × 2-2 + 1 × 2-3
= 0 + 2 + 0 + 8 + 16 + + 0 +
= 26 + = ≈ 26.625
To write the decimal number 37 in binary, how many binary digits are required ?
5
6
7
4
B.
6
Convertion chart to change decimal number 37 into binary number is as follows
The decimal number equivalent to a binary number 1011001 is
13
17
89
178
C.
89
Given, binary number = 1011001
Its equivalent decimal number
= 2° + 0 + 0 + 23 + 24 + 26
= 1 + 8 + 16 + 64
= 89
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 functions.
In the block diagram,
A is the square law device- This is a non-linear device and produces a non-linear output of message and carrier signals.
B is the band pass filter and it rejects high and low frequencies. It allows only a band of frequencies to pass through.