How are the RF signals transmitted and received ?

There are three basic requirement for communication (through RF Signals) to happen between two devices:

• Two or more devices that want to communicate
• Communication medium
• Few set of rules

Many components contribute to the successful transmission and reception of RF signals but very basic signal communication flow is discussed below:

First, there is a transmitter which begins the RF communication. The transmitter takes the initial digital data and modifies the data using a modulation technique (like QPSK, QAM etc.) to encode the data and convert that into the analog signal using DAC (digital to analog converter). That analog signal is fed to the transmitter chain which amplifies the signal to a higher power level and then signal is fed to the antenna. Antenna transmit that signal in the form of electromagnetic waves in the air.

On the other side, receiver device, receives the signal from the air.As there are many types of electromagnetic waves in the air, receiver device antenna receives the signal and filter out the desired signal. Then that signal is amplified and fed to the ADC (Analog to digital converter), which converts the analog signal to digital signal. Then this digital signal is demodulated and information is thus decoded.

In this above example, communication media is air. And set of rules are like which modulation, encoding, frequency of transmission, power etc.