RF Transmitter and an RF Receiver are the heart of any RF wireless communication system.
An RF transmitter is used to modulate the received data and transmit it through the antenna connected to it over the air as a microwave signal. These transmitted data are received by an RF receiver that operates at the same radio frequency as the transmitter.
In telecommunications, a radio transmitter is an electronic device that can generate radio waves through an antenna. The transmitter generates a radio frequency (alternating current), and then it will be applied to the antenna and it radiates radio waves.
RF Transceivers are used to communicate data/voice/video information over the wireless communication medium as electromagnetic waves. The received signal at the receiver will convert the IF frequency for further processing. Transceivers are mainly used in Radio and satellite communication, television signal trans-reception, and Cellular networks.
To learn more about RF and Microwave systems, we recommend you to check the following article.
To understand the RF Transceivers in a better way, we recommend checking and understanding more about the following components, which are prime components for the construction of Transceivers.
In this RF and Microwave Trans-receiver article, we will cover,
A transceiver is the combination of a transmitter and a receiver and is abbreviated as "TxRx".
RF Transceiver will be the combination of both the transmitter and the receiver and will have the capability to modulate and demodulate the original data signal.
The base of any Radio communication system is a transmitter and a receiver.
RF transmitter will modulate the received data signal and generate the RF signal and pass through the antenna, and the RF antenna, in turn, radiates the energy as radio waves over the wireless medium.
These transmitted radio waves will be captured by another antenna and will pass to the receiver. These receivers will demodulate the received signal from the carrier signal and regenerate the original data signal and pass it on to the system for further processing.
The device or a system used to transmit signal consists of information in the form of data, voice, video from one place to the other is known as RF transmitter and The device which receives and demodulates ( analog or digital ) and regenerate the original signal is known as RF receiver.
RF transmitters are classified on the basis of the modulation they will provide. Modulation is classified as Analog and Digital modulation. AM, FM, SSB, Direct, Superheterodyne are the major modulation type transmitter used in the Radio-communication domain.
AM transmitter uses amplitude modulation technology to convert information into modulated signals. In AM modulation the amplitude of the carrier signal is varied in accordance with the amplitude of the data signal which needs to transmit.
FM transmitter uses frequency modulation technology to modulate signals for transmission. In FM modulation the frequency of the carrier signal is varied in accordance with the amplitude of the original data signal.
In AM transmitter both sidebands ( Fc + Fm & Fc - Fm) are transmitted together. In SSB transmitter only transmit one sideband (either upper or lower band) to save bandwidth and power required for the transmission.
One of the prime direct conversion transmissions is QPSK( Quadrature Phase Shift Keying) transmitter. In it, the first signal is split into I and Q signals then mixes both the signal with LO (local oscillator) signal of 90-degree phase shift to one other. The mixed signals are summed up to obtain QPSK modulated signal and it is then amplified and transmitted.
In Superheterodyne Transmitter an AGC (Automatic gain control) is used to control the variation in the amplitude of the output signal from a Direct Conversion Transmitter.
RF receivers are classified on the basis of the demodulation it will support. Demodulations are also available as Analog and Digital types.
AM receiver receives the signal from the AM transmitter and extracts the required data signal using an amplitude detector and regenerates the original data.
FM receiver demodulated FM modulated signal using an FM detector circuit and regenerate the original data signal.
The received signal will pass through an ADC and the required digital data will be reproduced. Direct RF receiver is simple in design and a cost-effective solution.
In direct conversion, the receiver IQ demodulator is used to retrieve the I and Q signals from the received signal. It is also called a QPSK demodulator due to the 90-degree phase shift between the I and Q signals.
A superheterodyne receiver uses two mixers to retrieve the original data signal.
The application of an transmitters in RF communication system is to transmit the digital, audio, or video information in the form of an RF signal over a long distance.
The RF transmitter combines the original information signal to a carrier signal using any of the analog or digital modulation and transmits over the transmission channel. On the other end, the Receiver will receive the modulated signal from the antenna and it will demodulate and pass for further processing.
RF Trans-receiver will do both the functions of the transmitter and the receiver in a single module, hence it can be used to transmit and receive the information over a transmission channel.
When selecting an RF Transceiver for a system design, modulation is the prime factor that needs to consider. In addition, the designer needs to consider the following features of an RF Trans-receiver for the perfect design of the overall communication system.
The frequency of an RF Trans-receiver is the actual range of frequency signals broadcast and received from it. In general RF Tx/Rx will have the capability to tune the specific frequency of operation as per the application. Tx and Rx frequency will be different to avoid any signal interference between the transmitter and receiver.
An RF transceiver uses various analog and digital modulation and demodulation techniques such as AM, FM, QPSK, ASK, FSK, PSK, etc. For the short distance signal transmission, analog modulation will be suitable and for long-distance communications, digital modulations will be more error-free. RF transceivers with multiple modulation and demodulation capabilities are generally available.
The output power of the transmitter is the magnitude of power the internal amplifier of the transceiver module can provide for transmitting. Sensitivity is the minimum received signal power level needed for a transceiver to detect the signal. The higher the sensitivity is better is the performance of the RF transceiver.
As transceiver consists of many active components, power consumption needs to be considered during the selection of transceivers in the portable systems designs.
RF transceivers are available with different packages and dimensions with various RF connector options need to select as per the system's overall design requirements.
RF transceivers are widely used in radio communication systems for transmitting and receiving data. Now there are many manufactures are available that offer different transceivers with various modulation features and control options for power output.
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