Relay based Coupling Scheme of High Speed Communication data, High voltage DC And High Power Pulsed AC for Coaxial Cable

  • Manoj Gopalakrishnan DRDO-Naval Physical and Oceanographic Laboratory, Cochin - 682 021
  • Eldho Jacob DRDO-Naval Physical and Oceanographic Laboratory, Cochin - 682 021
  • Sona Kundukulam DRDO-Naval Physical and Oceanographic Laboratory, Cochin - 682 021
Keywords: Passive filters, Coupling schemes, Coaxial cable, Power line communication, Remote systems, Telemetry

Abstract

Coaxial cable telemetry is most commonly used in the field of underwater applications like data logging in oil rigs, underwater wireless modem, underwater acoustic measurements, borehole measurements, deep sea telemetry for sediment analysis, airborne sonars, imaging sonars etc. In all the above applications coaxial multicore cables are used. The design and development of relay based coupling scheme which helps to replace the multi core cable with a single core coaxial cable for telemetry application is described. Single core cable is suitable for long distance data communication. Multi core cables are generally heavy and due to the size, may not meet space constraints in complex systems. They are not economical too. The relay based coupling scheme is used to mix or separate the high speed bi-directional communication data, high voltage DC and high power pulsed AC. In single relay scheme one relay is used to switch the centre core of single core coaxial cable. Here the ground is common for both high power AC transmission and high speed bi-directional data path. A dual relay scheme is discussed where two relays are used to switch both the centre core and ground of the single core coaxial cable. This provides more ground isolation and can avoid ground lifting issues while high power AC transmission occurs. The simulation of the coupling scheme was done using PSpice®. A prototype of the coupling scheme was also made for analysis. Filter responses were analysed for each coupling path. The DC coupling filter has 85 Hz cut-off frequency at -3 dB. The cut-off frequency of high speed data coupler is 500 KHz at -3 dB. A 4.3KV peak to peak of 3 KHz and 7 KHz AC signals were transmitted and measurements were taken to analyse the effect of high voltage over different coupling paths. The 3 KHz signal has a peak of 61.88 dB and that of 7 KHz signal, the peak is 62.50 dB. The signal components of 3 KHz signal in the DC path has a voltage level of 9.375 dB and that of 7 KHz signal is 25.63 dB.

Author Biographies

Manoj Gopalakrishnan, DRDO-Naval Physical and Oceanographic Laboratory, Cochin - 682 021

Mr Manoj G. received MSc in Physics (specialisation in Electronics) from Kerala University Campus, Karyavattom in 2001. He works at Instruments Research and Development Establishment (IRDE), Dehradun, during 2005-2008 and works in the field of optical design for various day vision system, night vision system and thermal imagers. He is currently working as a Scientist at Naval Physical and Oceanographic Laboratory (NPOL), Cochin. His current research interests include, design and development of front end hardware and Telemetry development for Airborne Sonar, front end hardware design and Telemetry development of imaging sonar’s, Near Field Acoustic Characterization System (NACS), stepper motor controls. He has published papers related to challenges in Airborne Sonar’s, Sigma Delta Audio Cards, sensor less stepper motor controls, low noise amplifiers, linear power amplifiers for imaging sonars, simulink modelling etc. 

 

Eldho Jacob, DRDO-Naval Physical and Oceanographic Laboratory, Cochin - 682 021

Mr Eldho Jacob received his ME in Power Electronics and Drives from PSG College of Technology, Coimbatore in 2015. Currently working as Scientist at Defence Research and Development Organisation in the field of acoustic signal conditioning, data acquisition, power line communication and networking etc. He is currently working in the design of Airborne Sonar Telemetry and Data Acquisition, at Navel Physical and Oceanographic Laboratory. 

 

Sona Kundukulam, DRDO-Naval Physical and Oceanographic Laboratory, Cochin - 682 021

Dr Sona O. Kundukulam received the MSc (Electronics Science) in 1998 and PhD (Microwave Electronics) in 2003 from Cochin University of Science & Technology, India. In 2008, she joined Naval Physical & Oceanographic Laboratory (NPOL), Kochi. Presently she is working in the design and development of RF Systems for airborne Sonars. She has published more than 30 research paper in international and national journals and conferences. She is an associate member of IETE.

 

Published
2018-09-12
How to Cite
Gopalakrishnan, M., Jacob, E., & Kundukulam, S. (2018). Relay based Coupling Scheme of High Speed Communication data, High voltage DC And High Power Pulsed AC for Coaxial Cable. Defence Science Journal, 68(5), 487-493. https://doi.org/10.14429/dsj.68.11907
Section
Electronics & Communication Systems