Abstract: In a plural-sheet detector for a printing machine, which detects the number of sheets piled as the number of serial pulse signals, in which whenever the serial pulse signals are detected, the count value is provided, the count value being compared with a reference count value to provide a deviation value representative of the difference therebetween, and the deviation value is compared with a reference deviation value, so that when the deviation value is larger than the reference deviation value, the number of sheets is determined unacceptable.

Abstract: A mirror antenna employing a continuous mirror without a hole. A feed horn nd an electromagnetic lens, located behind a rotatable twist reflector (the mirror), collimates a beam toward a polarized reflector located near the twist reflector and tilted to aim energy toward the twist reflector. Energy reflected back toward the polarized reflector from the twist reflector passes through the polarized reflector to free space.

Abstract: An unfoldable antenna netting reflector includes a plurality of stiff ribs to which the reflector net is secured. These stiff ribs are pivoted to a central holding member and extend radially outwardly when the reflector is unfolded to spread out the reflector netting. In order to assure a trouble-free unfolding of such a reflector at any time levers (8, 9) are provided between two ribs each (2, 4; 4, 6). Tensioning cables (14, 16) running over rollers (17, 19) are operatively connected to the buckling joints (8',9') of these levers for straightening out the levers. The ends of the levers are pivoted to the respective rib and the levers are capable of buckling in but one direction. When the levers assume the stretched out position, they snap into a locked condition. A plurality of ropes arranged for operating a plurality of levers may be operated in unison. The levers are secured to the ribs either at a spacing from the radially outer end of the ribs, or they may be secured to these radially outer rib ends.

Abstract: An image spatial filter comprises back-to-back image cavities with means for coupling energy from one cavity to the other. Large angle of incidence energy is attenuated by each image cavity successively, thus providing a high degree of attenuation. Two quarter wavelength dielectric sheets with a ground plane between them and spaced from each by one-half wavelength form the image cavities. Slots in the ground plane provide coupling from one cavity to the other. Image spatial filters are not substantially more expensive than multi-layer dielectric spatial filters and are as easily fitted to existing antennas. But image spatial filters substantially reduce large angle passbands caused by the Brewster effect and by cavity resonance in dielectric spatial filters.

Abstract: The divider is formed by a dividing counter 7 to which an input pulse train is fed via an OR gate 3. The counter 7 has a fixed division ratio and the OR gate is controlled by a logic circuit which receives control pulses and controls the OR gate to remove one pulse from the input pulse train for each control pulse in order to change the overall division ratio of the divider. The invention is particularly suitable as an adjustable ratio divider for use in frequency synthesizers.

Abstract: An automobile antenna device comprising a first antenna section provided on a windshield glass for receiving a first wave band, a power supply terminal connected with one end of the first antenna section, a grounding terminal connected with the other end of the first antenna section and having a grounding portion which is adapted to be connected with ground, an electric power source adapted to be connected with the power supply terminal lead so that defogging current be supplied to the first antenna section, a second antenna section provided on the windshield glass for receiving a second wave band, a connecting section having one end connected with the second antenna section and the other end connected with the grounding terminal lead at least in the vicinity of the grounding portion.

Abstract: A broadband antenna features a diamond-shaped radiator. The radiator can be bent to form a selected dihedral angle to achieve omnidirectivity when a plurality of antennas having reflector screens are used. Two pairs of radiators can be placed in the turnstile configuration. A pair of shorted tubes can be used as a combination feed means and balun to avoid a separate balun.

Abstract: Ultra-high frequency antenna comprising a mirror constituted by a casing, whereof one face is metallized, and a support constituted by a metallic lattice, with connecting members fixing the mirror to its support. As the expansion coefficients of the mirror and the support differ, to prevent deformation of the latter, a connecting member located at the reference point which, for a revolution structure coincides with the apex, is rigid in all directions, whereas the other connecting members are semi-rigid, ensuring a certain flexibility in the expansion direction of the considered fixing points.Application to the antennas of radar, telecommunications and space telecommunications systems.

Abstract: An antenna apparatus for use in space which is foldable into a small package for storage in a space vehicle. The antenna apparatus utilizes a plurality of hinged members and diagonal tapes forming parallelogram frames, two opposite sides of which are hinged at the center to fold the frames in a given plane. Similar frames are hinged on the first frames in a second plane whereby a plurality of cubes are formed when all are unfolded.

Abstract: A bi-loop antenna system comprises an array of four bi-loop antennas equally spaced from the array axis and fed in phase and with equal power. Each antenna comprises an electrical conductor configured as two substantially identical open-ended coplanar loops, preferably square in shape, having colinear axes parallel to the array axis and electrically connected together, the open ends defining two closely spaced feed points at the middle of the array. The array is fed by a four-way coaxial power divider with output ports connected to the antennas, respectively, remote from the feed points thereof by coaxial lines of equal length. A balun comprising a portion of one of the loops of each antenna and a closely spaced coextensive conductive strip connects the inner and outer conductors of the coaxial cable to the two feed points, respectively, of the antenna. In a preferred embodiment, the conductors of each antenna are formed on a dielectric sheet or board by printed circuit techniques.

Abstract: An impedance matching network suitable for tuning an antenna includes a plurality of reactive elements and control circuits for selectively switching these elements into and out of the circuit. Each control circuit includes a pair of oppositely poled, normally reverse biased, PIN diodes connected in series across a reactive element and apparatus including a selectively controllable radiation responsive element for forward biasing the PIN diodes to thereby effectively switch a reactive element out of the network. In one arrangement, the reactive elements are formed from spaced, helically wound sections of a hollow conductive tube with the biasing voltages for the PIN diodes carried by conductors located within the tube.

Abstract: A dual band mirror antenna employing a continuous mirror without a hole. e-by-side feeds for each band and an electromagnetic lens, located behind a rotatable twist reflector (the mirror), collimate beams toward a pair of polarized reflectors located near the twist reflector and tilted to aim the reflected energy toward the twist reflector. One polarized reflector is reflective at the higher radiofrequency band and transparent at the lower radiofrequency band. The other polarized reflector is reflective at both bands. Energy directed back toward the polarized reflectors from the twist reflector passes through the polarized reflectors to free space.

Abstract: Twin lead transmission lines are positioned in close coupling relationship o linearly polarized and planar arrays of antenna radiating elements to provide a self contained instantaneous antenna test and measurement system. Near field energy from the transmission lines is coupled to the transversely arranged antenna dipole elements to permit testing without degrading antenna performance. Signals induced on the radiating elements are of uniform amplitude and linearly changing phase equivalent to those of a far field plane wave. Various tests such as antenna failure and performance characteristic measurements, including gain, pattern and phase difference, can be made automatically. A balanced power divider distributes RF power equally to the twin lead transmission lines and a system processor controls phase shifter scanning elements and analyzes the various output parameters to provide the desired test and measurement information concerning the selected array of dipoles and components.