Abstract: A method for real-time determining a concentration level of nitrate in a water sample collected from soil at a given site, the water sample contains an unknown composition and unknown concentration of DOC, the method includes: (A) during an offline stage: (a.1) obtaining a testing sample from the soil; (a.2) determining first and second wavelengths correlated, respectively, to concentration levels of the DOC and nitrate in the testing sample; (a.3) creating a calibration equation for this site; and, (B) during real-time: (b.1) separately impinging on a real-time water sample from the soil light in said two wavelengths; (b.2) determining respective absorbances by the real-time sample in said two wavelengths; and (c) substituting the respective absorbances in the calibration equation to obtain the nitrate concentration in the real-time sample.

Abstract: The invention relates to a system for determining a level of nitrate in a water sample, including: (a) an optical flow cell which is at least partially transparent and which is configured to contain a sample of water; (b) a first illuminator for illuminating the sample by light in a first wavelength, and a first photodetector for collecting the first-wavelength illumination, following the light passage through the sample; (c) a second illuminator for illuminating the sample within the cell by light in a second, fluorescence-exciting wavelength, and a second photodetector for collecting illumination in a third, fluorescence-emission wavelength from the sample; and (d) an analysis unit for determining the combined effect of nitrate+DOC within the sample on the absorbance of light, determining a concentration of DOC within the sample based on fluorescence emission from the sample, and subtracting the effect of DOC from the combined effect of nitrate+DOC on the absorbance, thereby to determine a concentration of

Abstract: A system for measuring with the aid of light absorption spectrometry the concentration of one or more analytes in porewater in soil, the system comprising: one or more monitoring unit(s), each monitoring unit comprising a porewater sampler (1), an optical flow cell (2) with a tube connecting the liquid inlet port of said optical flow cell to said porewater sampler; and vacuum arrangement to enable extraction of porewater; at least one light source (5) for generating a light beam to be transmitted through said optical flow cell (2); and at least one detector (8) for obtaining spectral information from the beam exiting said optical flow cell. A method of measurement is also provided.

Abstract: A system for measuring with the aid of light absorption spectrometry the concentration of one or more analytes in porewater in soil, the system comprising: one or more monitoring unit(s), each monitoring unit comprising a porewater sampler (1), an optical flow cell (2) with a tube connecting the liquid inlet port of said optical flow cell to said porewater sampler; and vacuum arrangement to enable extraction of porewater; at least one light source (5) for generating a light beam to be transmitted through said optical flow cell (2); and at least one detector (8) for obtaining spectral information from the beam exiting said optical flow cell. A method of measurement is also provided.

Abstract: A method and apparatus for improving the transmission quality of a free space optical bus between circuitry elements in high speed computing, communication and signal processing systems. Use is made of an adaptive algorithm that learns the transmission properties of the bus, and selects or adjusts transmission paths or characteristics to provide optimum bus performance. Each transmitter on the bus transmits a signal which is generally measured by all of the receivers on the bus, and the measured signals are used to generate a matrix which maps desired transmission along information links, and cross-link interference.

Abstract: A method for transferring information within a cellular communications network (20), consisting of transmitting an optical carrier from a first network-element (26A) of the network, modulating the optical carrier (57, 59) with the information, and detecting the modulated optical carrier in an avalanche photo-diode (APD) (150) in a second network-element (24A) of the network so as to recover the information. The method includes altering a gain of the APD responsive to a level of the optical carrier so as to prevent saturation of the APD. Other methods and apparatus are also provided for transferring the information via the optical carrier, and also for using the information transferred.

Abstract: Apparatus for transferring information within a cellular network, including a base-station transceiver system (BTS) positioned at a first location, and an antenna assembly, positioned at a second location remote from the first location. The BTS includes communication control circuitry which generates down-link radio-frequency (RF) signals and processes up-link RF signals, and first transducer circuitry which modulates a first beam of unguided electromagnetic radiation with the downlink RF signals and demodulates a second beam received from the antenna assembly to recover the up-link signals.