Speech signals is in the range of
3700 Hz to 7000 wavelength
20 Hz to 20 kHz frequency
300 Hz to 3100 Hz frequency
540 kHz to 1600 kHz frequency
To transmit a signal of frequency ωm with a carrier frequency ωc, in AM transmission, the bandwidth of the filter and amplifier is
ωm
2ωm
ωc
ωc − ωm
If the height of TV tower is increased by 21%, then the transmission range is enhanced by
10 %
5 %
15 %
25 %
The range of a communication system can be extended by a
modulator
transmitter
repeater
receiver
For commercial telephonic communication, the frequency range for speech signals is
50 Hz to 1000 Hz
3000 Hz to 4500 Hz
300 Hz to 3100 Hz
5000 Hz to 6500 Hz
The role of envelope detector in an AM receiver is to
retrieve the message signal
rectify the AM signal
modify the AM signal
modulate the message signal
Identify the mismatched pair
Noise — Unwanted signals
Repeater — Communication satellite
Attenuation — Srengthening of signal
Demodulation — Retrieval of information
Pick out the wrong statement.
Analog signals provide a continuous set of values
Digital signals represent values as discrete steps
Analog signals utilise the binary system
Digital signals can be processed by logic gates
A ground receiver receives a signal at 5 MHz, transmitted by a ground transmitter at a height of 320 m, which is 110 km away from it. Then it can communicate through (radius of the Earth, R = 6400 km)
space waves
ground waves
sky waves
both sky and ground waves
The power radiated by a linear antenna of length l at wavelength λ is
directly proportional to l
inversely proportional to λ
inversely proportional to λ2
directly proportional to λ2