Communication systems

The output transducer of the communication system converts the radio signal into

• Sound

• Mechanical energy

• Kinetic energy

• None of the above

The signal is affected by noise in communication system

• At the transmitter

• At the modulator

• In the channel

• At the receiver

The variation of frequency of carrier wave with respect to the amplitude of the modulating signal

• Amplitude modulation

• Frequency modulation

• Phase modulation

• Pulse width modulation

The internationally accepted frequency deviation for the purpose of FM broadcasts

• 75kHz

• 68kHz

• 80kHz

• 70kHz

The frequency range of 3 MHz to 30 MHz is used for

• Ground wave propagation

• Space wave propagation

• Sky wave propagation

• Satellite communication