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Semiconductors
Published in Daniel D. Pollock, PHYSICAL PROPERTIES of MATERIALS for ENGINEERS 2ND EDITION, 2020
Some applications of these devices include tuning, switching, logic circuits, and parametric amplification where high speed and stability are needed. One very common use is for automatic frequency control for radio receivers.
Transmitters and receivers
Published in Mike Tooley, David Wyatt, Aircraft Communications and Navigation Systems, 2017
Radio receivers use tuned circuits in order to discriminate between incoming signals at different frequencies. Figure 3.13 shows two basic configurations for a tuned circuit; series and parallel. The impedance-frequency characteristics of these circuits are shown in Figure 3.14. It is important to note that the impedance of the series tuned circuit falls to a very low value at the resonant frequency whilst that for a parallel tuned circuit increases to a very high value at resonance. For this reason, series tuned circuits are sometimes known as acceptor circuits. Parallel tuned circuits, on the other hand, are sometimes referred to as rejector circuits.
Contemporary Wireless Technologies
Published in G. S. V. Radha Krishna Rao, G. Radhamani, WiMAX, 2007
G. S. V. Radha Krishna Rao, G. Radhamani
Microwave transmission is based on the same principles as radio transmission. The microwave networks require a direct transmission path, high transmission towers, and antennas. Satellite communications are used for a variety of broadcasting applications. The two most popular frequency bands for satellite communications are C-band (frequency range 5.9 to 6.4 GHz for uplink and 3.7 to 4.2 GHz for downlink) and Ku-band (frequency range 14 to 14.5 GHz for uplink and 11.7 to 12.2 GHz for downlink). The radio transmission system consists of a transmitter and a receiver. The main components of a radio transmitter are a transducer, an oscillator, a modulator, and an antenna. A transducer converts the information to be transmitted to an electrical signal. An oscillator generates a reliable frequency that is used to carry the signal. A modulator embeds the voice or data signal into the carrier frequency. An antenna is used to radiate an electrical signal into space in the form of electromagnetic waves. A radio receiver consists of an antenna, an oscillator, a demodulator, and an amplifier. An antenna captures radio waves and converts them into electrical signals. An oscillator generates electrical waves at the carrier frequency that is used as a reference wave to extract the signal. A demodulator detects and restores modulated signals. An amplifier amplifies the received signal that is typically very weak.
Compliance, mass distribution and contact forces in cursorial and scansorial locomotion with biorobotic physical models
Published in Advanced Robotics, 2021
Robert Siddall, Toshihiko Fukushima, Drilon Bardhi, Buna Perteshoni, Albulena Morina, Era Hasimja, Yll Dujaka, Gezim Haziri, Lina Martin, Hritwick Banerjee, Ardian Jusufi
The second climbing robot is actuated by four servomotors (HSR-2645CR, 53 g mass), each driving a single wheg at a prescribed speed, with a maximum torque of 0.78 N·m per wheg, or a combined maximum forward force of 6.4 kg (ten times body mass), based on the maximum wheg radius of 5 cm (Figure 4B). The robot chassis is laser cut from fibreboard, while the mounting hardware, whegs and compliant tail are fabricated using a fused deposition 3D printer. The servos are controlled by a radio receiver module, which accepts speed commands from the operator. The compliant tail has an embedded soft capacitive sensor (bendlabs, one axis sensor), from which data is recorded over a Bluetooth serial connection. The main structure of each wheg is printed using PLA plastic, and a separately printed compliant set of spines, made from TPU elastomer is bonded to the traction surface of each wheg to facilitate climbing.
Sensor integration for real-time data acquisition in aerial surveillance
Published in Australian Journal of Electrical and Electronics Engineering, 2022
Wahyu Rahmaniar, Ardhi Wicaksono Santoso
In this system, the quadrotor-type UAVs used with the flight commands are received by the radio receiver. Each rotor speed is controlled via an electronic speed controller (ESC) that received a signal. A GPS, two servo motors, a FSR and an XBee module connected to the mainboard. The XBee module is used to send UAV flight data to the ground station and receive ground station commands to move the video transmitter (camera) and gripper. An ultrasonic sensor is installed on each side of the quadrotor frame to detect obstacles when flying, and one sensor is mounted with the camera. Due to limitation of the I/O pins of the processor, every ultrasonic sensor is switched using transistors in the additional board. (Figure 2(a, b, c))
Design and Analysis of 2.4 GHz Low-Noise, High-Gain 0.18 μm CMOS Cascode Low-Noise Amplifier for IRNSS Applications
Published in IETE Journal of Research, 2022
D. Jahnavi, G. Kavya, Anjana Jyothi Banu
Low-Noise Amplifier has an utmost importance in radio receiver circuits. As an integral part in receiver LNA must provide high-gain, low-noise figure, better input and output matching with good linearity. The basic three topologies, as shown in Figure 1, provide proper device configuration.