Some of the commonly used physical transmission media are twisted copper cable, good quality coaxial cable and radio frequency bands.

Some of the main features which make the transmitter complex are higher clock speed, higher transmit power, directional antennas and need for a linear amplifier.

The basic transmission-reception consists of three blocks – transmitter, transmission medium, receiver.

A signal can be recovered from its sampled version by using an ideal low pass filter.

Some of the conditions which must be satisfied in a digital communication system are high data rate, high fidelity, low bandwidth, low transmit power and low transmitter and receiver complexity.

Sampling theorem is used for converting continuous time signal to discrete type signal and vice versa.

The main features of a receiver which increases its complexity are synchronization of carrier, phase, and timing and multiple parallel receiver chain.

Larger bandwidth is available when operating frequency bands are higher.

Air, water and copper cable can be used as transmission media in low frequency band communication.

Ground wave communication can take place in both low frequency and medium frequency bands.