baseband signal in frequency modulation. The instantaneous amplitude of the baseband signal modifies the phase of the carrier signal keeping the amplitude and frequency constant in phase modulation If the EM waves transmitted by the transmitter glide over the surface of the earth to reach the receiver, then the propagation of EM waves is called ground wave propagation. The mode of propagation in which electromagnetic waves radiated from an antenna, directed upwards at large angles gets reflected by the ionosphere back to earth is called sky wave propagation. The process of sending and receiving information signal through space is called space wave communication.
The satellite communication is a mode of communication of signal between transmitter and receiver via satellite. Fiber-optic communication is a method of transmitting information by sending pulses of light through an optical fiber. Radar basically stands for Radio Detection and Ranging System. It is one of the important applications of communication systems for remote sensing.
Mobile Communication is used to communicate with others in different locations without the use of any physical connection like wires or cables. - - - - - - - - Unit electronics and Communication C O N C EP T M AP Internet Ex-OR NOR NAND OR NOT Oscillator Electronics and Communication Systems Electronics Communication systems Conductor Energy band structure Diodes Semiconductor types Satellite communication Semiconductor devices Intrinsic semiconductor Bi-junction transistor Logic gates Extrinsic semiconductor Types Uses AND Ground wave Space wave Sky wave AM FM PM NPN transiator Switch PNP transiator Amplifer p-n junction didode Special purpose diodes Zener diode n -type p -type Insulators Semiconductor LED Photo diode Solar cells Modulation Elements of Communication system Propagation of Electromagnetic waves Fiber optic communication RADAR Mobile communication Important Communication systems - - - - - - - - Unit electronics and Communication EVALUATION c) Photovoltaic action d) Carrier flow . The light emitted in an LED is due to a) Recombination of charge carriers b) Reflection of light due to lens action c) Amplification of light falling at the junction d) Large current capacity.