Signal sensing and measuring in fibre optic systems with light pulse width detecting
First Claim
Patent Images
1. A fibre optic sensor control system, comprising:
- means for generating a pulsed source electrical signal;
electro-optical converter means for converting the source electrical signal into an optical signal;
optical fibre means for transmitting the optical signal with a variable transmittance;
opto-electrical converter means for converting an optical signal received from the fibre into an electrical signal; and
detector means for detecting the pulse width of the received electrical signal.
1 Assignment
0 Petitions
Accused Products
Abstract
In a fibre optic sensor control system using an optical fibre (14) responsive to an applied external pressure P and through which a series of pulses are transmitted, a detector (20, 22) is responsive to the pulse-width of the received pulses rather than merely their amplitude. This results in less susceptibility to interference and also makes the system less sensitive to changes in the transfer characteristics of the electro-optical convertor (12) and/or of the opto-electrical convertor (20) and/or the maximum transmittance of the optical fibre.
32 Citations
24 Claims
-
1. A fibre optic sensor control system, comprising:
-
means for generating a pulsed source electrical signal; electro-optical converter means for converting the source electrical signal into an optical signal; optical fibre means for transmitting the optical signal with a variable transmittance; opto-electrical converter means for converting an optical signal received from the fibre into an electrical signal; and detector means for detecting the pulse width of the received electrical signal. - View Dependent Claims (2, 3, 4, 6, 7, 8, 9, 10, 20)
-
-
5. A signal detector system comprising:
-
opto-electrical convertor means for converting a pulsed optical signal received from an optical fibre into an electrical signal; and detector means for detecting the pulse width of the electrical signal.
-
-
11. A fibre-optic sensor system comprising:
-
means for generating a pulsed optical signal, optical fibre means for receiving the optical signal, means for varying an optical property of the fibre in dependance upon an external condition, signal detector means including timing means for timing the duration of a predetermined portion of the pulses of the signal, and means for indicating the value of the external condition in dependence upon the timed signal portion. - View Dependent Claims (12, 13)
-
-
14. A fibre-optic sensor control system comprising:
-
pulsed optical source means for producing optical pulses, optical fibre means for receiving optical pulses form the source means, and detector means for detecting pulses received via the fibre means and for generating a corresponding pulsed electrical signal to control the optical source so as to maintain the pulse width of the pulsed electrical signal substantially constant. - View Dependent Claims (15, 16, 17, 18)
-
-
19. A detector system for a fail-to-safe control system comprising:
-
opto-electrical converter means for converting a pulsed optical signal received from an optical fibre into an electrical signal, and detector means for detecting the pulse width of the electrical signal, the detector means being operable not to respond to an electrical pulse having less than a predetermined pulse width. - View Dependent Claims (21)
-
-
22. A method of detecting an abnormal condition, comprising the steps of:
-
providing an optical fibre arranged to be subjected to pressure by said abnormal condition, said optical fibre having first and second ends; launching a pulsed optical signal into said first end of said optical fibre; detecting a corresponding pulsed optical signal from said second end of said optical fibre, to provide a signal having a pulse width which varies according to pressure on said fibre; and generating an indication of said abnormal condition when said pulse width is less than a predetermined value.
-
-
23. A method of measuring pressure, comprising the steps of:
-
providing an optical fibre having first and second ends and mounted so as to be subjected to pressure; launching a pulsed optical signal into said first end; detecting a corresponding pulsed optical signal at said second end and providing a corresponding signal having a pulse width which varies according to pressure on said fibre; and controlling the pulse width of said launched optical signal in dependence upon said detected optical signal so as to retain said detected pulse width substantially constant.
-
-
24. In an optical fibre sensing method comprising the steps of launching a pulsed optical signal into said optical fibre at a first end thereof and detecting a corresponding signal at a second end thereof, the steps of timing the duration of received signals, and of rejecting received pulses of shorter than a predetermined duration.
Specification