摘要:
For short-distance communication systems, particularly for optical-waveguide links in the subscriber area, it is proposed to operate the standard single-mode optical waveguide for long-distance applications, which is optimized for the wavelength range from 1300 nm to 1600 nm, with optical transmitters and optical receivers whose operating wavelengths lie clearly below the cutoff wavelength of the optical waveguide. By means of a suitable stable laser-waveguide coupling, it is ensured that single-mode operation is achieved, which is necessary to transmit digital signals at high bit rates. The increased loss of the optical waveguide at 800 nm can be accepted because of the relatively short length of subscriber lines. Both unidirectional and bidirectional transmission over a single optical waveguide using wavelength-division or modal multiplexing is possible.
摘要:
A mining device for subsurface extraction of raw materials off rocks includes bracing means for the reversible bracing of the mining device in a hollow space, a frame, and tunneling means stationarily connected with the bracing means, whereby the frame is movable by the tunneling means in a predefined direction. A rotatable roller is arranged on the frame, at the circumference of which cutting tools and clearing devices are arranged such that a rectangular mining cross-section can be created and such that the mining device and also the frame of the mining device is movable into a mining tunnel created by these cutting tools.
摘要:
The wet-fastness properties of cellulose materials dyed with sulfur dyestuffs is improved by treating the cellulose materials, before, during or after dyeing, with a polymer which is a copolymer or homopolymer of a monomer of the formula ##STR1## wherein R.sup.1 and R.sup.2 denote, for example, hydrogen or (C.sub.1 -C.sub.22)-alkyl; R.sup.3 and R.sup.4 denote hydrogen or methyl; and Y.sup..crclbar. denotes, for example, a monovalent anion.
摘要:
A fiber optic connector is disclosed capable of joining in proper alignment the uncentered ends of two optical fibers mounted in ferrules. Each ferrule is rotatably supported inside an eccentric bore of a connector sleeve by means of a rotatable cage whose balls or rollers have different diameters. The two cylindrical connector sleeves are capable of being mated in a connector receptacle with the optical fibers therein adjusted to exact lateral alignment.
摘要:
The invention is directed to a method of evaluating the signal of an infrared thermometer for measuring human body temperature, in which the infrared thermometer includes a probe adapted to receive thereon a probe cover or protective film sufficiently transparent to infrared radiation, and in which on a measuring operation performed with the probe cover or protective film in “installed” condition the signal is evaluated, so that a measuring operation is performed also when the probe cover or protective film is not installed, with an appropriate allowance being made for the consequently more intensive infrared radiation by different signal evaluation.
摘要:
The invention is directed to a method of computing the radiation temperature of a body from the signals of a radiation and an ambient temperature sensor, and further to a radiation thermometer, in particular a clinical radiation thermometer. In the method of the present invention, computation of the temperature is not using the Stefan Boltzmann law, but rather, a polynomial is used, preferably a third-degree polynomial, which is adjusted to the radiation-optical properties of the thermometer in the relevant wavelength range. The reciprocal value of the sensitivity of the radiation sensor is preferably represented as a polynomial as well. In this manner, the computation of a fourth root or divisions which are otherwise customary are avoided, enabling the necessary computations to be also performed, for example, by a 4-bit microprocessor with great speed.
摘要:
A method of calibrating a radiation thermometer including a radiation sensor and an ambient temperature sensor, the method including the steps of using a first radiation standard having a known temperature T.sub.S (1) and with the ambient temperature sensor at a first ambient temperature T.sub.U (1), using the radiation thermometer to read the temperature of the first radiation standard and while doing so, measuring a first output signal U(1) of the radiation sensor; using a second radiation standard having a known temperature T.sub.S (2) and with the ambient temperature sensor again at the first ambient temperature T.sub.U (1), using the radiation thermometer to read the temperature of the second radiation standard and while doing so, measuring a second output signal U(2) of the radiation sensor; and calibrating the radiation sensor and the ambient temperature sensor by using the values obtained for U(1) and U(2) and without using a value for T.sub.U (1) that is derived from measuring an output of the ambient sensor.
摘要:
A circuit arrangement for enforcing an intrinsically safe situation in a hazardous zone features a first switching device that lies in the series arm and a second switching device that lies in the shunt arm. If a fault occurs that would violate the conditions of intrinsic safety, the first switching device is initially blocked and the second switching device is switched through with a time delay such that the output terminals are mutually short-circuited. In addition, a monitoring device is provided for monitoring the load conditions at the switching device arranged in the series arm.
摘要:
An optical switching unit is disclosed which permits switching from faulty components to standby components in optical transmission systems. A component in this connection may be a transmit laser or an optical fiber, for example. The optical switching unit (OSE) according to the invention contains an n×m optical space switch (ORS) whose ports (P1A . . . PNA; P1B . . . PMB) are monitored by photodiodes (M1A, M1B). The photodiodes provide a control unit (SE) with information as to whether and, if so, what signals are arriving at the ports. The control unit (SE) controls the position of the optical switch (ORS) in accordance with program instructions. The switching unit controls itself, i.e., incorporation of a higher-level control center is not necessary. It thus allows very short switching times and has many applications; it is particularly suitable for use in modular optical transmission systems.
摘要:
Known optical amplifiers, which are used in a light transmission path to amplify the light signals to be transmitted, have the disadvantage that the semiconductor lasers, used as pump lasers therein, are very sensitive to feedback.According to the invention, the operating current of such pump lasers (4) is modulated at a high frequency, which causes the pump laser to operate in a multi-mode, thereby making it insensitive to feedback. For example, the operating current is DC, on which AC is superimposed.In the event the optical amplifier has two pump lasers, their operating current is also modulated. Both pump lasers are then advantageously alternately switched on and off at a sufficiently high switching frequency, which also prevents reciprocal interference.