A band width of 15 MHz is available for transmission. If maximum signal frequency used for modulating the corrier is 15 kHz then low number of stations which can broadcast without any inference with each other ) in this band is
1.300
2.400
3.457
4.500
A certain transmitter radiates 9 kW of power with carrier unmodulated and 10.125 kW when the carrier is modulated. The modulation index is
1.60%
2.55%
3.40%
4.50%
A charge having oscillating frequency 2 MHz. The wavelength will be None of these
1.150 KM
2.200 KM
3.250 KM
4.None of these
A modulated wave has maximum amplitude of 750 mV and minimum amplitude of 250 mV. Then percentage modulation is
1.33%
2.50%
3.75%
4.100%
A sinusoidal carrier wave of frequency of 15 MHz is modulated by audio signal of frequency of 5 KHz then upper frequency component of the resultant modulated wave is
1.15 MHz
2.10 MHz
3.15.005 MHz
4.14.995 MHz
Electronic transmission of a document to a distant place via telephone line is called
1.Fax
2.Modem
3.E-mail
4.Telephone
For a FM wave the carrier is 160 MHz modulating frequency is 15 kHz and frequency deviation of 1 MHz if modulating frequency is doubled the band width will be
1. 5 MHz
2.3 MHz
3.2 MHz
4.1 MHz
For a FM wave the carrier is 160 MHz modulating frequency is 15 kHz and frequency deviation of 1 MHz. The band width required is
1.2 MHz
2.1 MHz
3.20 KHz
4.10 MHz
If a carrier wave of amplitude to mV is modulated by an audio signal of amplitude 2 mV then amplitude of LSF and USF is given by
1.0.2 mV
2.0.5 mV
3.1 mV
4.2 mV
If the wavelength of the electromagnetic radiations is doubled frequency of the electromagnetic radiations will be
1.same as earlier
2.half the earlier
3.double the earlier
4.four times the earlier
If total power content of an AM wave is 2.64 kW at 80% modulation then power content of each side band are
1.1.32 kW
2.2.64 kW
3.660 watt
4.320 watt
Modem is a device which performs
1.Modulation
2.Demodulation
3.Rectification
4.Modulation and demodulation
Process of sending and receiving the information with the help of some suitable system is called
1.Communication
2.Tranxmission
3.Fax
4.Modem
The dc voltage applied at each station in case of coaxial cables is
1.1400 V
2.1300 V
3.1350 V
4.1250 V
The frequency of a wave propagating in D-region having refractive index is 0.5 is
1.400 Kc/s
2.300 Kc/s
3.207.33 Kc/s
4.None of these
The glass of optical fibre has refractive index 1.6 and is clad with another glass of refractive index 1.52. The numerical aperture will be
1.0.499
2.0.459
3.0.0625
4.0.352
The maximum frequency at which coaxial cable operates
1.2500 mc/s
2.2000 mc/s
3.3000 mc/s
4.300 mc/s
The maximum usable frequency in F-layer with original frequency of 50 MHz will be
1.181 MHz
2.150 MHz
3.250 MHz
4.300 MHz
The optical source is used to
1.convert electrical energy into optical energy
2.deted the signal
3.demodulate the electrical signal
4.All of the above
The satellite that is used in ship to shore and shore to ship communication is
1.Comsat
2.Marisat
3.Telstar
4.Intelstar
The UHF band ranges from
1.30 to 300 MHz
2.30 to 3000 MHz
3.20 to 2000 MHz
4.30 to 300 KHz
Total power content of an AM waves is 1500 watt. For a 100% modulation power content of carrier should be
1.500 watt
2.1000 watt
3.1500 watt
4.None of these
Which of the following is use for analogue to digital conversion ?
1.Amplitude modulation
2.Pulse code modulation
3.Frequency modulation
4.Phase modulation
Which of the following pair belongs to the same communication system
1.Telephony Fax
2.Telegraphy E-mail
3.Teleprinting
4.Communication satellite Telemetry Mobile Phone