In this note, we are going to learn a topic called “What is Radio Broadcasting?“, we will know about transmitter and receiver section block diagram as well. Welcome to Poly Notes Hub, a leading destination for engineering notes for diploma and degree engineering students.
Author Name: Arun Paul.
What is Radio Broadcasting?
Radio Communication refers to the radiation of radio waves by the transmitting station, their propagation through space, and reception by the radio receiver. The figure shows the general concepts of radio broadcasting, transmission, and reception. As a matter of convenience, the entire system can be divided into three parts: transmitter, radio wave transmission, and reception or receiver.
Radio Broadcasting Block Diagram
Here we discuss about the block diagram of radio broadcasting system –
1. Radio Transmitter
The broadcasting station houses the transmitter, which is an extremely significant piece of equipment. Its function is to generate radio waves for transmission into space. A transmitter’s key components are the microphone, audio amplifiers, oscillator, and modulator.
- Microphone: A microphone is a device that converts sound into electrical waves. When the speaker speaks or a musical instrument is played, the variable air pressure on the microphone produces an audio electrical signal with a frequency that corresponds to the original signal. The microphone output is fed into a multistage audio amplifier to increase the intensity of the weak signal.
- Audio amplifier: The audio signal from the microphone is quite faint and requires amplification. This task is completed by cascaded audio amplifiers. The amplified output from the last audio amplifier is delivered to the modulator, which renders the modulation process.
- Oscillator: The function of an oscillator is to generate a high frequency signal known as a carrier wave. Typically, a crystal oscillator is utilized for this purpose. Radio frequency amplifier stages increase the power of the carrier wave to a sufficient level. Most broadcasting stations have carrier wave power of several kilowatts. Such considerable power is required to transmit the signal over the requisite distances.
- Modulator: The amplified audio signal and carrier wave are supplied into the modulator. The audio signal is superimposed on the carrier wave in an appropriate manner. The resulting waves are referred to as modified or radio waves, and the process is known as modulation. Modulation allows the transmission of an audio signal at the carrier frequency. As the carrier frequency is quite high, the audio signal can be broadcast across long distances. The radio waves from the transmitter are fed into the transmitting antenna or aerial, from which they are radiated into space.
2. Radio Waves Transmission
The transmission antenna sends radio waves into space in all directions. Radio waves move at 3×10⁸ m/sec, which is the speed of light. Radio waves are electromagnetic waves that share the same general features. These are comparable to light and heat waves, except they have longer wavelengths. It is worth noting that radio waves are transmitted without the use of wires. Electrical energy can be emitted into space at high frequencies, as is easily demonstrated.
3. Radio Receiver
The radio wave causes a small amount of emf in the receiving antenna. A modest voltage is provided to the radio receiver. The radio waves are first amplified, and then a signal is retrieved from them via the demodulation method. Audio amplifiers amplify the signal before feeding it to the speaker, where it is reproduced as sound waves.
Advantages
- Radio can reach a large audience, including those living in isolated and rural places where other kinds of media may not be available.
- Radio programs are less expensive to develop and transmit than television shows or online streaming.
- Radio stations frequently focus on local news, events, and issues, which helps to increase community engagement and understanding.
