Signal processing system of multiplexed fiber bragg grating sensor using CDMA

摘要

A signal processing system of a multiplexed FBG sensor using CDMA comprises a pseudo random bit sequences (PRBS) generator (11) for generating pseudo random bit sequence; a LED (12) for light-emitting at a pseudo random bit from the PRBS generator; a fiber coupler (13) for transmitting a light signal from the LED into a FBG sensor portion (14) and passing signals reflected by the FBG sensor portion herethrough; the FBG sensor portion (14) for receiving/reflecting the light signal via an optic fiber to forward it back to the fiber coupler (13); an FBG filter portion (15) for filtering the signal reflected by the FBG sensor portion and passed through the fiber coupler; a photo detector (16) ,for converting the light signal from the FBG filter portion into the electrical signal; a delaying portion (17) for delaying a pseudo random bit signal from the PRBS generator for a predetermined time period; a mixing portion (18) for mixing the delay signal from the delaying portion and the output signal from the photo detector; and at least one auto-correlation device (19) for integrating or auto-correlating the signal from the mixing means, thereby enhancing the stability of the system and the linearity of a signal to be measured to applied strain.