A radio receiver is an electronic device used in radio communications. It receives the radio waves that are transmitted and converts the information they carry into a form you can use.
Radio receivers are not just limited to the radio anymore. They are used in television, remote controls, mobile phones, wireless networking systems, etc.
How does a receiver work?
The main component of a receiver is its antenna. The antenna receives energy from the incoming radio waves. It then converts the energy into a radio frequency AC voltage that is applied to the receiver’s input. The radiofrequency is then converted into a usable form.
Functions of a radio receiver
A radio receiver has three main functions:
Filtering the radio frequencies
The radio waves transmitted from different transmitters travel simultaneously in the atmosphere without interrupting each other. The antenna of the receiver receives all these waves.
However, out of all radio waves, the receiver needs to convert the waves of a specific frequency. How does it achieve that? That’s where the bandpass filter comes in.
The bandpass filter uses the frequency of the waves to separate them. It allows the waves of the desired radio transmission to pass through, blocking the other waves. The filter then passes on the filtered transmission to the ground for conversion.
Amplifying the recovered signal
The power of the radio waves decreases with the distance they travel. If the receiver is farther than a few miles of the transmitter’s location, it receives a weak signal. The amplifier of the receiver uses electric power from a plug or a battery to strengthen the signal by increasing its amplitude.
The receiver measures the degree of amplification by sensitivity. For those of you who might not know about it, sensitivity refers to the minimum signal strength necessary to receive the signal clearly. It is measured in microvolt.
The receiver has several stages of amplification.
Demodulating the modulated signal
Before the transmitters send out radio waves, they combine with it the data in the process of modulation. Therefore, after filtering and amplifying these waves, the receiver demodulates them to extract the information. It contains a demodulator to do the job.
There are different types of demodulators:
- Amplitude Modulation or AM Demodulator
- Frequency Modulation or FM Demodulator
- Frequency Shift Keying or FSK Demodulator
The type of demodulator varies in accordance with the type of modulation. The FSK demodulator is specifically used to demodulate digital data.
Once the signal is demodulated, the amplifier is used to increase their power. The information is then converted into the form you can comprehend, like audio, video, etc. by a transducer.
Other applications of the radio receiver
- Data communication
- Satellite communication
- One-way voice communication
- Two-way voice communication
- Broadcast television reception
- Remote control
- Radio telescope
- Measuring receiver
Radio receivers have a long history and are used for a wide range of purposes. It is, therefore, essential that you understand their operation and functions in order to choose the best one for you.