Abstract: An apparatus and method of measuring free water, also known as undissolved water, in hydrocarbon fuel. A housing defines a chamber and is adapted to receive a fluorescein impregnated filter pad in the chamber between a UV light source and a light sensor. The filter pad is exposed to the fuel causing the free water to react with the fluorescein and is then placed within the chamber between the light source and sensor. The UV light strikes one side surface of the filter pad and excites the reacted fluorescein thereby causing light emitted from the UV light reacted fluorescein filter pad opposite side surface to strike the light sensor. An output from the light sensor is proportional to the fluorescein on the filter pad which reacted with free water and is used for providing an output value representative of the free water present in the hydrocarbon fuel.

Abstract: An apparatus and method of measuring free water, also known as undissolved water, in hydrocarbon fuel. A housing defines a chamber and is adapted to receive a fluorescein impregnated filter pad in the chamber between a UV light source and a light sensor. The filter pad is exposed to the fuel causing the free water to react with the fluorescein and is then placed within the chamber between the light source and sensor. The UV light strikes one side surface of the filter pad and excites the reacted fluorescein thereby causing light emitted from the UV light reacted fluorescein filter pad opposite side surface to strike the light sensor. An output from the light sensor is proportional to the fluorescein on the filter pad which reacted with free water and is used for providing an output value representative of the free water present in the hydrocarbon fuel.

Abstract: An apparatus and method of measuring free water, also known as undissolved water, in hydrocarbon fuel. A housing defines a chamber and is adapted to receive a fluorescein impregnated filter pad in the chamber between a UV light source and a light sensor. The filter pad is exposed to the fuel causing the free water to react with the fluorescein and is then placed within the chamber between the light source and sensor. The UV light strikes one side surface of the filter pad and excites the reacted fluorescein thereby causing light emitted from the UV light reacted fluorescein filter pad opposite side surface to strike the light sensor. An output from the light sensor is proportional to the fluorescein on the filter pad which reacted with free water and is used for providing an output value representative of the free water present in the hydrocarbon fuel.

Abstract: An apparatus and method of measuring free water, also known as undissolved water, in hydrocarbon fuel. A housing defines a chamber and is adapted to receive a fluorescein impregnated filter pad in the chamber between a UV light source and a light sensor. The filter pad is exposed to the fuel causing the free water to react with the fluorescein and is then placed within the chamber between the light source and sensor. The UV light strikes one side surface of the filter pad and excites the reacted fluorescein thereby causing light emitted from the UV light reacted fluorescein filter pad opposite side surface to strike the light sensor. An output from the light sensor is proportional to the fluorescein on the filter pad which reacted with free water and is used for providing an output value representative of the free water present in the hydrocarbon fuel.

Abstract: An optical logic device is provided by an interferometer having an output which defines a logic state 1 or 0 in dependence upon an interference condition existing in the interferometer. Each arm of the interferometer contains a semiconductor optical amplifier in which the effect of cross phase modulation is utilized to modulate the phase of light transmitted through the respective arms. Optical signals are counter propagated through one or both of the arms in order to provide the cross modulation and thereby enable the interference condition to be set to one or other of the logic states. Automatic level control is provided at inputs to the interferometer and between successive stages of logic device. The method has application to high frequency digital optical communication systems where all optical logic operations are required.

Abstract: A compression amplifier processes both the audio modulating signal to the transmitter, and the audio output from the receiver, in a conventional amplitude modulated transceiver. Unique switching circuitry provides isolation between transmitter and receiver inputs to, and outputs from, the compression amplifier.