Abstract: Extracting a displacement component includes: receiving a received signal resulting from an optical signal being scattered by the plurality of particles in the fluid, the received signal comprising a displacement component; mixing the received signal with a local oscillator signal to generate a mixed signal; detecting the mixed signal via a set of one or more detectors and generating a set of one or more electrical signals based on the detection; demodulating the set of one or more electrical signals to obtain the displacement component; and outputting the displacement component.

Abstract: A system and method for optical communication is disclosed comprising a transmitter configured to transmit a signal wherein a first channel is in a USB spectrum but not in an LSB spectrum; and a second channel is in an LSB spectrum but not in the USB spectrum; and wherein an unmodulated optical carrier is suppressed; and a receiver configured to receive the transmitted signal.

Abstract: A system and method for optical communication is disclosed comprising a transmitter configured to transmit a signal wherein a first channel is in a USB spectrum but not in an LSB spectrum; and a second channel is in an LSB spectrum but not in the USB spectrum; and wherein an unmodulated optical carrier is suppressed; and a receiver configured to receive the transmitted signal.

Abstract: A device designed to float in a home pool and sound an alarm when the water is disturbed, which is peculiarly sensitive to disturbances in the water, including a transducer for sensing noise in the water, a high frequency filter connected to the transducer, a saturable amplifier connected to the filter, an integrator connected to the amplifier, and a trigger circuit connected to the integrator for initiating an alarm. The integrator has a rise time on the order of fifty milliseconds so that it rejects moderately loud disturbances unless they repeat many times within a short period of time, as is the case in noise reflected off the walls of an average size pool. The decay time of the integrator exceeds five hundred milliseconds so that the integrator output builds up over the period of at least two or three major noise pulses of a typical moderate splash in water.