High resolution demodulation technique for Sagnac fibre optics gyroscopes using a low frequency quasi-synchronous clock

A simple technique which employs a low frequency quasi-synchronous clock was developed to measure duty-cycles with high resolution. For the same measurement resolution, the proposed circuit can operate with clock frequencies typically 1000 times lower than in conventional digital duty-cycle measurem...

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Bibliographic Details
Published in:	International journal of electronics and communications Vol. 66; no. 2; pp. 150 - 152
Main Authors:	Fernandes, Alecio P., Ferreira, E.C., Siqueira Dias, J.A.
Format:	Journal Article
Language:	English
Published:	Elsevier GmbH 01-02-2012
Subjects:	Duty-cycle measurement Fibre optics gyroscopes Quasi-synchronous clock Zero-cross demodulator Zero-cross demodulator Quasi-synchronous clock Duty-cycle measurement Fibre optics gyroscopes
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Summary:	A simple technique which employs a low frequency quasi-synchronous clock was developed to measure duty-cycles with high resolution. For the same measurement resolution, the proposed circuit can operate with clock frequencies typically 1000 times lower than in conventional digital duty-cycle measurement system with synchronous clock. The proposed circuit is composed of only two Digital Direct Synthesis integrated circuits and one Complex Programmable Logic Device. Experimental results obtained with a prototype of the proposed time measurement system show that, for an emulated zero-cross fibre optics gyroscope output signal with 100 kHz and Δ T = 100 ns (duty-cycle of 50.25%), a resolution of 100 ps can be achieved using a 10.01 MHz frequency clock.
ISSN:	1434-8411 1618-0399
DOI:	10.1016/j.aeue.2011.06.003