Robust signal processing for communication systems

1983 ◽  
Vol 21 (1) ◽  
pp. 20-28 ◽  
Author(s):  
S. Kassam ◽  
H. Poor
Keyword(s):  
Signal Processing ◽  
Communication Systems ◽  
Robust Signal Processing

RF photonics signal processing in subcarrier multiplexed optical-label switching communication systems

2003 ◽  
Vol 21 (12) ◽  
pp. 3155-3166 ◽  
Author(s):  
Zuqing Zhu ◽  
V.J. Hernandez ◽  
Min Yong Jeon ◽  
Jing Cao ◽  
Zhong Pan ◽  
...  
Keyword(s):  
Signal Processing ◽  
Communication Systems ◽  
Label Switching ◽  
Rf Photonics

scholarly journals The Limpet: A ROS-Enabled Multi-Sensing Platform for the ORCA Hub

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3487 ◽  
Author(s):  
Mohammed Sayed ◽  
Markus Nemitz ◽  
Simona Aracri ◽  
Alistair McConnell ◽  
Ross McKenzie ◽  
...  
Keyword(s):  
Signal Processing ◽  
Condition Monitoring ◽  
Wind Turbines ◽  
Communication Systems ◽  
Offshore Structures ◽  
Classification Approach ◽  
Communication Techniques ◽  
Sensing Platform ◽  
Online Classification ◽  
Monitoring Process

The oil and gas industry faces increasing pressure to remove people from dangerous offshore environments. Robots present a cost-effective and safe method for inspection, repair, and maintenance of topside and marine offshore infrastructure. In this work, we introduce a new multi-sensing platform, the Limpet, which is designed to be low-cost and highly manufacturable, and thus can be deployed in huge collectives for monitoring offshore platforms. The Limpet can be considered an instrument, where in abstract terms, an instrument is a device that transforms a physical variable of interest (measurand) into a form that is suitable for recording (measurement). The Limpet is designed to be part of the ORCA (Offshore Robotics for Certification of Assets) Hub System, which consists of the offshore assets and all the robots (Underwater Autonomous Vehicles, drones, mobile legged robots etc.) interacting with them. The Limpet comprises the sensing aspect of the ORCA Hub System. We integrated the Limpet with Robot Operating System (ROS), which allows it to interact with other robots in the ORCA Hub System. In this work, we demonstrate how the Limpet can be used to achieve real-time condition monitoring for offshore structures, by combining remote sensing with signal-processing techniques. We show an example of this approach for monitoring offshore wind turbines, by designing an experimental setup to mimic a wind turbine using a stepper motor and custom-designed acrylic fan blades. We use the distance sensor, which is a Time-of-Flight sensor, to achieve the monitoring process. We use two different approaches for the condition monitoring process: offline and online classification. We tested the offline classification approach using two different communication techniques: serial and Wi-Fi. We performed the online classification approach using two different communication techniques: LoRa and optical. We train our classifier offline and transfer its parameters to the Limpet for online classification. We simulated and classified four different faults in the operation of wind turbines. We tailored a data processing procedure for the gathered data and trained the Limpet to distinguish among each of the functioning states. The results show successful classification using the online approach, where the processing and analysis of the data is done on-board by the microcontroller. By using online classification, we reduce the information density of our transmissions, which allows us to substitute short-range high-bandwidth communication systems with low-bandwidth long-range communication systems. This work shines light on how robots can perform on-board signal processing and analysis to gain multi-functional sensing capabilities, improve their communication requirements, and monitor the structural health of equipment.

scholarly journals Additive manufacturing of highly reconfigurable plasmonic circuits for terahertz communications

2020 ◽  
Author(s):  
Yang Cao ◽  
Kathirvel Nallappan ◽  
Hichem Guerboukha ◽  
Guofu Xu ◽  
Maksim Skorobogatiy
Keyword(s):  
Signal Processing ◽  
Real Time ◽  
Carrier Frequency ◽  
Communication Systems ◽  
Low Loss ◽  
Wet Chemistry ◽  
Waveguide Bends ◽  
Terahertz Communications ◽  
Optical Circuits ◽  
Low Dispersion

Terahertz communications is a booming field in rapid development. While in most of the existing terahertz communication systems, modulated THz carrier wave is transmitted via free-space communication channels, the THz waveguide-based integrated solutions can be of great utility both at the transmitter and receiver ends. Thus, at the transmitter end they can be used for steering, beam forming, and multiplexing of the THz signals. At the receiver end, terahertz waveguide-based solutions can be used as reliable interconnects (especially in the geometrically complex environments, ex. intra-vehicle communications), as well as for real-time analogue signal processing such as filtering and demultiplexing. More generally, waveguide-based THz optical circuits are indispensable for miniaturization and mass production of cost-effective THz communication systems. In this work, we present comprehensive numerical, fabrication and optical characterization studies of a new type of modular THz integrated circuits based on the micro-encapsulated two-wire plasmonic waveguides. Particular attention is payed to the design of optimized components such as waveguides, couplers and waveguide Bragg gratings to realize easy to handle, highly reconfigurable terahertz circuits capable of complex functionalities such as multiplexing and demultiplexing. The basic element of all the developed subcomponents is a low-loss low-dispersion two-wire waveguide suspended inside of a protective micro-sized enclosure (cage) using deeply subwavelength dielectric supports. The high resolution stereolithography 3D printing and wet chemistry metal deposition techniques are employed to fabricate such waveguides where the THz light is mainly confined in the air gap between the two wires. First, the straight waveguides are characterized using continuous-wave THz spectroscopy system with the measured transmission loss and group velocity dispersion (GVD) of 6 m-1 and -1.5 ps/THz·cm respectively at the carrier frequency of 140 GHz. Next, waveguide bends and a Y-coupler based on the two coalescing waveguide bends are studied. We find that due to the presence of a cage, the curved two-wire waveguides show smaller bending loss than the free-standing two-wire waveguides of similar geometry. Additionally, we find that relatively tight bends of ~5cm-radius can be well tolerated by adding less than ~10 m-1 propagation losses to the curved waveguide propagation loss. Next, we design and fabricate the two-wire waveguide Bragg gratings by hot stamping a periodic sequence of metal strips onto a paper sheet and inserting it into the air gap between the two-wire waveguides. The geometry of the grating featuring a Bragg frequency of 140 GHz is studied theoretically and numerically, and the optimal waveguide gratings are then realized experimentally. Such structures can have bandwidths as high as ~20 GHz. Finally, using thus developed modular components, a two channel THz Add-Drop Multiplexer (ADM) is demonstrated for the operation at 140 GHz carrier frequency and featuring a spectral width of 2.8 GHz. We believe that the reported modular platform based on the micro-encapsulated two-wire waveguides can have a strong impact on the field of integrated optical circuits for THz signal processing and potentially sensing due to ease of device fabrication (standard 3D printers and wet chemistry), modular design and high degree of reconfigurability, low-loss and low-dispersion of the underlying waveguides, as well as high potential for the real-time tunability of the optical circuits due to ease of access of the modal fields inside the controlled in-cage environment.

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