摘要:
A dc to ac electric power inverter which includes a series static inverter circuit, having at least two controlled rectifiers interconnected by a self-quench circuit and alternately switched on and off by trigger pulses. The triggering frequency is made equal to the a c output signal frequency divided by an integer greater than the number of rectifier pairs in use so that the upper frequency limit of the output signal is enhanced.
摘要:
A modulator comprising a diode to which both the modulating signal and the signal to be modulated are applied. The diode circuit comprises an element whose resistance varies inversely in relation to the amplitude of the direct current detected in the diode. This element is preferably a diode.
摘要:
A sequential switching device using solid-state components, consisting in a bar of gallium arsenide monocrystal, in which adjacent diodes are formed, the terminals of same sign of which are arranged on the two opposite faces of the bar. These diodes, which are virtually insulators below a certain threshold voltage applied to their terminals are conductive beyond it; they emit photon radiation in the conductive condition, and, conversely, change from the insulating to the conductive condition under the effect of said photon radiation. By combining these diodes in sets of three in order to form three groups to the terminals, of which there are applied voltage pulses which succeed one another without interruption or overlap, propagation of switching along the set of diode is achieved, each diode irradiating its two neighbours, when in the conductive condition.
摘要:
The invention relates to optical printers for printing onto a photosensitive substrate a succession of characters arranged in parallel lines. The optical printer according to the invention comprises a matrix of radiant energy sources capable of forming planar patterns representative of the characters to be printed; the pencils of radiant energy emerging from the matrix are transmitted toward the substrate across an afocal optical system wherein an acousto optical deviator element is positioned.
摘要:
A plurality of complex replicas, or estimates, of each transmitted information bit, based on the parity-check equations, are formed in addition to the simple replica which the corresponding received information bit constitutes. To each replica is associated a likelihood magnitude of the form logm(1P)/P where P is the probability of the replica being erroneous. The decision is made by an algebraic adder forming the sum of the likelihoods of different estimates of the information bit, those likelihoods being associated with a plus or minus sign according to whether the binary value of the replica is 0 or 1. The sign of the sum gives the decoded value, and the absolute value of the sum, the likelihood of the decoded value.
摘要:
A field effect transistor (F.E.T.), comprising two control gates disposed in side-by-side relationship and capable of being operated at frequencies higher than 1 GHz, is provided. A gate G1 is deposited at the bottom of a trench T1, recessed in the F.E.T.''s semiconductive layer and connected to a contact stud K1. It encloses the source S of the transistor and is surrounded, at a distance of the order of 10 microns, by a gate G2 deposited at the bottom of a trench T2 recessed in the F.E.T.''s semiconductive layer and connected to a contact stud K2. The drain D of the transistor surrounds the trench T2 and the stud K2. The cross-section of the trenches is of the order of 1 micron by 1 micron.
摘要:
The present invention relates to double-diffraction optical correlators. According to the invention there is provided a multi-channel optical correlator for shape recognition wherein the lenses and the filters are all constituted by patterns of fringes ; each channel is fed from a quasi-monochromatic and quasi-punctiform light source, which may be spatially incoherent.
摘要:
A metal matrix of photo-M.O.S. devices, transparent to radiation is provided. A gate is associated with each of the collectors of the matrix. Said gate overlaps partly onto the associated collector. The other part of the collector is covered by a layer of insulating material and a thick layer, connected to the gate of the neighbouring element of the same line in a plane located between the two collectors. The collectors of one and the same column are electrically connected. The gates of one and the same line are electrically connected.
摘要:
A fixed control station in a zone of high traffic density exchanges information with mobile stations aboard vehicles within that zone by short-range radiocommunication. The control station has an antenna in the form of a coaxial cable, with leakage losses, terminated by a dissipative load at one end while its other end is coupled to a transmitter supplying it with a frequency-modulated outgoing carrier destined for the vehicles within range. The outer conductor of the cable is grounded, at its end proximal to the load, through a parallel-resonant network tuned to the frequency of an incoming carrier from transmitterequipped vehicles; the other end of this conductor, remote from the load, is grounded through a similarly tuned circuit whose inductive branch forms the primary of a transformer coupling it to an associated receiver. A vehicle equipped with a car radio may have switchover means for selectively listening in on a radio program or on traffic information from the control station; a monitoring relay may respond to such traffic information to reverse a switch normally positioned for radio reception.
摘要:
Delay line in the form of a helix for a travelling wave tube is provided including a plurality of hollow conductive tube elements forming turns of the helix. Fluid distribution means communicates with the tube elements for circulating fluid therethrough and includes alternate feeds to each of said turns and alternate outputs from each of said turns, said alternate feeds and outputs forming conductive elements coupled to the extremities of each of the conductive tube elements of the helix.