Other

Frank Frungel

Martin Spies

A discharge lamp with high intensity and high local stability is disclosed, which is suitable for use as a light source in a visibility meter. A light receiver also suitable for use in a visibility meter is disclosed. The discharge lamp has a discrete anode chamber and a discrete cathode chamber which are both filled with gas and which are interconnected via a capillary tube. One end of the capillary tube is adjacent a cathode located within the cathode chamber, while the other end of the capillary tube projects forwardly of a region in which the anode is adjacent the capillary tube. Plasma is confined within the capillary tube, resulting in high local stability and high intensity light output. The light receiver utilizes a photosensitive element and an electrical filter which is so designed that response of the light receiver is calibrated to include or coincide with that portion of the visible light spectrum which carries maximum energy.

Visibility meter and components used therein

Two embodiments of the visibility meter are disclosed. In the first embodiment, light transmitted from the light transmitter and light received by the light receiver is propagated in a conical beam. The beams are so oriented that they include an obtuse angle. In the first embodiment, a partition blocks all direct transmission of light from the light transmitter to the light receiver. In the second embodiment, direct transmission of light from the light transmitter to the light receiver takes place through the partition, but is limited to a predetermined level.

Forward-scatter visibility meter

In a ceilometric system, light pulses are emitted from a transmitter towards overhead clouds and reflected back down towards a receiver which generates a photodetector signal transmitted by a gate whose gating interval is shifted in time relative to the light-pulse emission instant to define successive range steps. During each dwell at a particular gating interval and range step, the photodetector signal is integrated to develop an integral signal for that range step. The integral signal for each range step is digitalized and stored in a digital storage circuit, ordered in correspondence to the sequence of the range steps. A microprocessor searches for the largest one of the stored integral signals and derives a ceilometric indication in dependence thereon.

Ceilometric method and apparatus

An arrangement for determining the density of natural fog in the atmosphere in which a spark lamp serving also as a flashing beacon projects a beam of light composed of consecutive pulses through the fog laden atmosphere so as to scatter part of the light to thus form consecutive pulses of scattered light in a defined region of the path of the light beam, the intensity of which is proportional to the density of the fog in this region, and in which light pulse receiver means are constructed and arranged relative to said region so as to receive only the scattered light pulses which are measured by the receiver means to thereby indicate the density of fog in the aforementioned region.

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Zurich, Switzerland

Frank Frungel