Abstract: A distributed fiber sensor system based on Brillouin scattering. Two DFB lasers are included that are frequency offset locked to each other. The frequency offset is approximately equal to the Brillouin shift in optical fibers of about 11 GHz. The locking is realized by first modulating the output of one DFB laser with an electro-optic modulator to generates side bands that are about 11 GHz from the carrier, and then by locking the other DFB laser to the upper side band with a PID controller which controls its driving current.

Abstract: A fiber optic strain sensor, an optical pulse generator generates an initial optical pulse, and launches it into an optical fiber-optical strain probe chain through an optical circulator. The scattered optical power in the optical fiber and optical strain probe chain is sent to an optical receiver, also via the optical circulator. The optical strain probes are attached to a structure whose strain is to be measured. Strain in the structure causes the fiber bend loss to change in the strain probe, and causes the scattered optical power received by the optical receiver to change accordingly. From the change of the output of the optical receiver and the time required for the scattered optical power to travel from the probe, the strain at each of the probes is calculated.

Abstract: An electric security fence. An electric signal generator generates an initial electric signal. The generated initial electric signal is transmitted through a transmission line. The transmission line will generate a reflected electric signal when the transmission line is disturbed by the presence of a human or animal at a disturbance area. A receiver receives the reflected electric signal and forwards it to a signal processing unit. The signal processing unit calculates the location of the disturbance area after receiving the reflected electric signal. In one preferred embodiment, the signal processing unit calculates the location of the disturbance area by determining the amount of time required for the reflected signal to travel from the disturbance area.

Abstract: An electric security fence. An electric signal generator generates an initial electric signal. The generated initial electric signal is transmitted through a transmission line. The transmission line will generate a reflected electric signal when the transmission line is disturbed by the presence of a human or animal at a disturbance area. A receiver receives the reflected electric signal and forwards it to a signal processing unit. The signal processing unit calculates the location of the disturbance area after receiving the reflected electric signal. In one preferred embodiment, the signal processing unit calculates the location of the disturbance area by determining the amount of time required for the reflected signal to travel from the disturbance area.

Abstract: An electric security fence. An electric signal generator generates an initial electric signal. The generated initial electric signal is transmitted through a transmission line. The transmission line will generate a reflected electric signal when the transmission line is disturbed by the presence of a human or animal at a disturbance area. A receiver receives the reflected electric signal and forwards it to a signal processing unit. The signal processing unit calculates the location of the disturbance area after receiving the reflected electric signal. In one preferred embodiment, the signal processing unit calculates the location of the disturbance area by determining the amount of time required for the reflected signal to travel from the disturbance area.

Abstract: An electric security fence. An electric signal generator generates an initial electric signal. The generated initial electric signal is transmitted through a transmission line. The transmission line will generate a reflected electric signal when the transmission line is disturbed by the presence of a human or animal at a disturbance area. A receiver receives the reflected electric signal and forwards it to a signal processing unit. The signal processing unit calculates the location of the disturbance area after receiving the reflected electric signal. In one preferred embodiment, the signal processing unit calculates the location of the disturbance area by determining the amount of time required for the reflected signal to travel from the disturbance area.