Q.Elaborate on the basic elements of communication system with the necessary block diagram.

Step 1. Information (baseband/input signal). The original speech, music, picture or computer data to be communicated.

Step 2. Input transducer. Converts the information (in whatever physical form it starts, e.g. sound) into an equivalent electrical baseband signal. The microphone is the standard example.

Step 3. Transmitter. Feeds the electrical signal from the transducer into the communication channel. It contains: an amplifier (boosts the transducer's weak output); an oscillator (generates the high-frequency sinusoidal carrier wave, whose energy is proportional to its frequency); a modulator (superimposes the baseband signal onto the carrier, producing the modulated signal); and a power amplifier (raises the modulated signal's power to cover a large distance).

Step 4. Transmitting antenna. Radiates the modulated radio signal into space in all directions, travelling as an electromagnetic wave at the speed of light, $3\times10^8$ m s$^{-1}$.

Step 5. Communication channel. Carries the electrical signal from transmitter to receiver with as little noise/distortion as possible; either wireline (wires/cables/optical fibres -- point-to-point, unsuitable for long distances, e.g. telephone) or wireless (free space via antennas, used for long distances, e.g. mobile/radio/satellite).

Step 6. Noise. An undesirable electrical signal, man-made (vehicles, motors) or natural (lightning, solar radiation), that attenuates or degrades the transmitted signal in the channel; it cannot be eliminated but can be reduced.

Step 7. Repeaters. A combination of transmitter and receiver that receives, amplifies, and retransmits a weakened signal on a fresh carrier to extend the range -- a communication satellite is the best example.

Step 8. Receiver. Consists of a receiving antenna (converts the incoming EM wave into an RF signal), a demodulator (extracts the baseband signal from the modulated carrier), and further amplifier/detector circuits.

Step 9. Output transducer. Converts the recovered electrical signal back into its original form -- sound (loudspeaker), pictures (picture tube/monitor), etc.

Step 10. Attenuation and Range. Attenuation is the loss of signal strength while propagating through a medium; range is the maximum distance over which the signal is received with sufficient strength.

Step 11. Block diagram. Figure 10.4 draws exactly this chain: Input Transducer -> Amplifier -> Modulator (fed by the Oscillator's carrier wave) -> Power Amplifier -> Transmitting Antenna -> Communication Channel -> Receiving Antenna -> Demodulator -> Amplifier -> Output Transducer.

Walk through every numbered element from information to output transducer, in order, describing the block diagram as you go.

• Omitting noise, attenuation, range or repeaters, treating only the transmitter-channel-receiver chain as 'the elements'.
• Forgetting to describe or reference the block diagram, which the question explicitly asks for.