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Abstract
An autocorrelation technique, which involves the correlation of a signal with its delayed version, could be used to demodulate the FM (Frequency Modulation) and PM (Phase Modulation) signals in a simple cost-effective manner. In this paper, an attempt has been made to understand the working principle of the autocorrelation technique for FM and PM demodulations. From the working principle, several design equations have been derived and these equations have been verified with the experimental results obtained from a 70 MHz autocorrelation-type FM receiver designed and developed indigenously. The demodulation of FM signal directly at RF (radio frequency) level has also been demonstrated using an autocorrelation-type C-band FM receiver at 4180 MHz.
ACKNOWLEDGEMENTS
The authors are thankful to the Deputy Director, ICA, Shri V K Hariharan for his constant encouragement and motivation for writing this paper. The authors also extend their sincere gratitude to the spacecraft checkout team for their help to carry out the experimental works. Finally, the authors are very much thankful to all the colleagues in the Spacecraft Checkout Group (SCG) who have helped to complete this task directly or indirectly.
DISCLOSURE STATEMENT
No potential conflict of interest was reported by the author(s).
Additional information
Notes on contributors
Tosicul Wara
Md Tosicul Wara is a scientist at UR Rao Satellite Centre. He joined ISRO in 1993. Presently, he is the head of GEOSAT RF & Payload Checkout Division-1 (GRCD-1) of Spacecraft Checkout Group at U R Rao Satellite Centre, Bangalore. His field of interest includes satellite communication, global navigational satellite system (GNSS), and microwave measurement & instrumentations. He is a fellow of the Institution of Electronics and Telecommunication Engineers (IETE).
Karri V. R. Dinesh Kumar Reddy
Karri V R Dinesh Kumar Reddy is a scientist at U R Rao Satellite Centre. He joined ISRO in the year 2016. His research interest includes the design of pressure windows, microwave & RF communication systems. Presently, he is working as an engineer in GEOSAT RF & Payload Checkout Division (GRCD). Email: [email protected]
Usha Bhandiwad
Usha Bhandiwad is a scientist at UR Rao Satellite Centre (URSC), and presently, she is the Group Director of Spacecraft Checkout Group (SCG) of URSC. She received the BE degree in electronics and communication engineering from Karnataka University, Dharwad. Presently, her work areas include design, development and realization of simulators and providing automation for spacecraft testing. Email: [email protected]