RF, Microware and Optical Frequency Communications – A Review of Technologies
10. Transmission and receiver (Tx/Rx) chain, in terrestrial communication network
Overview of the transmission and receiver chain in a typical terrestrial communication network:
Transmission (Tx) Chain:
1. Data source: The transmission chain begins with a data source, such as a computer or other device, that generates the data to be transmitted.
2. Encoding: The data is typically encoded using a digital modulation scheme, such as phase-shift keying (PSK) or quadrature amplitude modulation (QAM), to convert the digital data into a form that can be transmitted over the airwaves.
3. Upconversion: The modulated signal is then upconverted to a higher frequency using a mixer and local oscillator. This process is known as modulation upconversion.
4. Amplification: The upconverted signal is then amplified by a power amplifier to increase its strength and ensure that it can be transmitted over a long distance.
5. Transmission: The amplified signal is then transmitted over the airwaves, typically using an antenna.
Receiver (Rx) Chain:
1. Reception: The receiver chain begins with the reception of the transmitted signal using an antenna. The received signal is typically very weak, and may be affected by noise, interference, and other factors.
2. Amplification: The received signal is amplified by a low-noise amplifier to increase its strength and reduce the impact of noise and interference.
3. Downconversion: The amplified signal is then downconverted to a lower frequency using a mixer and local oscillator. This process is known as demodulation downconversion.
4. Filtering: The downconverted signal is then filtered to remove unwanted noise and interference, and to select the desired frequency band.
5. Demodulation: The filtered signal is then demodulated using a digital signal processing (DSP) algorithm to recover the original digital data.
6. Decoding: The demodulated signal is then decoded to convert the digital data back into its original form, such as text, audio, or video.
These are the basic steps involved in transmitting and receiving data over a terrestrial communication network. The actual implementation can vary depending on the specific communication protocol and hardware used.
11. Typical power levels used in Tx chain
The power levels used in the transmission (Tx) chain and the frequency ranges involved can vary depending on the specific application and the communication protocol being used. However, here are some typical power levels and frequency ranges for common types of terrestrial communication systems:
1. Wi-Fi: Wi-Fi networks typically operate in the 2.4 GHz and 5 GHz frequency bands, and the Tx power levels range from around 30 mW (milliwatts) to 1 W (watt) depending on the specific device and regulatory requirements.
2. Cellular networks: Cellular networks typically operate in the 700 MHz to 2.5 GHz frequency range, with power levels ranging from around 0.1 W to 2 W for handheld devices and up to several hundred watts for base stations.
3. Satellite communication: Satellite communication systems operate at a wide range of frequencies, from L-band (1 GHz to 2 GHz) to Ka-band (26.5 GHz to 40 GHz) and beyond. The power levels used in satellite Tx chains can vary widely depending on the specific system, but can range from a few watts to several kilowatts.
4. Broadcasting: Broadcasting systems, such as television and radio, typically operate in the VHF (very high frequency) and UHF (ultra high frequency) bands, which range from 30 MHz to 1 GHz. The power levels used in broadcasting can range from a few watts for handheld devices to several megawatts for high-power broadcasting transmitters.
It's worth noting that regulatory agencies around the world set limits on the maximum allowable Tx power levels and frequency ranges for different types of communication systems, in order to prevent interference with other systems and ensure safety. These limits can vary depending on the country and the specific application.
