Abstract:
In a circuit for translating to a variable carrier frequency an input signal with a fixed carrier frequency, comprises said signal at said variable frequency, the linearity of the amplifier being obtained by means of a negative feedback loop between the output of the amplifier and of the signal input of the frequency converter and this feedback loop including a frequency converter for re-translating the feedback signal to the frequency of the input signal, the variable phase-shifter ensuring the addition in phase opposition, in an adder, of the input signal and of the feedback signal is inserted between this adder and the frequency converter feeding the amplifier. This location of the phase-shifter causes the gain of the circuit to be substantially independent of the variable frequency which is used. In addition the phase-shifter is automatically controlled.
Abstract:
In a delay line of an electron tube for amplifying or generating microwaves, externally of and parallel to a main conductor helix within which an electron beam travels axially, there extends a secondary helix which has a pitch and a diameter half the size of those of the main helix and which is so arranged that its turns electrically contact those of the main helix at several locations along a generatrix common to both helices. The field effect generated by the secondary helix substantially diminishes parasitic phenomena that appear in a delay line having a main helix of large diameter.
Abstract:
A magnetic system for deflecting the beam in an electron accelerator, comprising two sets of electromagnets which deflect the beam through a total angle of 90* and are located within in a single mounting, pivotally mounted about the axis of the entry beam.
Abstract:
A radar system referred to as a noise radar system operating in a continuous or quasi-continuous mode, which transmits a noise signal toward a target. The receiver signal from the target is summed up with a replica of the transmitted signal and the composite signal obtained is processed in a first multichannel receiver wherein it is directed in a preferred manner, to square law detectors. The signal issuing from the detectors is a sinusoid the frequency of which is proportional to the range of the target. This signal is then processed in another multichannel receiver through a switch which transforms the spatial representation delivered at the output of the detectors into a temporal representation, the range information being obtained at the output of a distance channel of the second receiver.
Abstract:
A vessel, filled with a vapor, the quantum transition of which is to be detected, has photosensitive transducer means applied around the walls thereof in a region remote from the axis of a pumping beam applied to the vessel, so that the photosensitive transducers are responsive to essentially all radiated energy impinging on the walls of the vessel at random angles with respect to the axis of the pumping beam; the cell is included in apparatus including an RF generator of variable frequency, the output of which is coupled to the cell to generate within the cell a radio-frequency electromagnetic field. The frequency of the RF generator is controlled by a feedback control circuit coupled to the output from the photosensitive transducers, so that, when their output is a maximum, the frequency of the RF generator will be locked in.
Abstract:
A visual display system for visualizing an image represented by a video signal comprising an analogue-to-digital converter for translating this video signal into a digital signal, a memory for storing this digital signal while supplying it continuously and a digital-to-analogue converter connected to the memory and restituting an analogue image signal to a conventional display tube.
Abstract:
Certain UHF electron tubes using the interaction between an electromagnetic wave and an electron beam comprises a delay line made up of periodic elements having an aperture for the transit of said beam, the height of said elements decreasing at the end of the delay line to match said end to the input and/or output connections. The present invention allows to avoid the interception of a certain fraction of the beam by the element part comprised between the aperture and the edge of said element, when said part, at said end of the delay line, is reduced. The improvement relates to UHF electron tubes operating in very short wavelengths.
Abstract:
The load is formed as a plurality of terminal elements, one being the last and the others being complementary thereto; each one includes an external conductor and an internal conductor, the complementary terminal elements further including a peripheral conductor coaxially surrounding each complementary element and electrically connected to an adjacent peripheral conductor of an adjacent element, the open end of the external conductor of the first terminal element being interconnected with the adjacent end of the peripheral conductor of the next adjacent complementary element, the external conductors of two adjacent terminal elements being interconnected by a material transparent to the energy to be dissipated, or directly connected thereto; preferably, a resistive element may form the interconnection between an interior conductor and the closed end of an external conductor, and cooling means may be provided (such as by the formation of gaps and making the internal conductor hollow) to additionally dissipate a load.
Abstract:
An optical multiplier, such as a fly''s eye lens projects a symbol to be recognized on a plurality of masks, which are subdivided into strips, each strip of the mask having predetermined transparencies and transmitting elementary sections of the image to associated photoelectric transducers which are connected to logic circuits identifying those of the transducers associated with any one strip which, conjointly, have an extreme (e.g., maximum) output signal. Preferably, optical or electrical weighting elements are interposed to optimize the outputs of the transducers associated with the various masks.
Abstract:
The invention relates to optical pumping magnetometers wherein an absorption cell is optically pumped with a pumping light source emitting two spectrum lines building up a doublet. The magnetometer according to the invention uses an absorption cell filed with a mixture of an alkali vapor and a buffer gas. The efficiency of the optical pumping is increased by insertion between the pumping source and the cell of an optical arrangement capable of circularly polarizing in mutually opposite directions the pumping radiations corresponding to the above-mentioned spectrum lines.