Hydrophone demodulator circuit and method
CA 1339426 C · Owner: Bunn, James S. · Inventors: Layton, Michael R.; Bunn, James S.
Overview
Its claims, description and drawings are in the Canadian Patents Database.
Open the CIPO recordAbstract From the Canadian patent
The optical signal in a fiber optic interferometer is phase modulated to provide a carrier signal for phase changes caused by changes in a physical parameter being sensed. The signal is then demodulated to measure changes in the parameter. A crystal oscillator frequency reference and passive filtering cause the circuit to have low phase noise. Digital phase shifters provide mixer references that have low phase noise and stable gain. The signal processing techniques of the present invention are applicable to sensor arrays using a single carrier excitation source, time demultiplexing of individual carrier signals and demodulation of each sensor carrier signal. This demodulator circuit is also …
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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.
Why it's free to use
- Granted September 2, 1997. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 2, 2014.
- We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
Timeline
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Sources & verification
Official CIPO records
Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.