Abstract: A read/write head circuit that insures the equivalence between the driving signal frequency and the resonance of the tank made up of an inductive sensor in parallel with a capacitor. The invention makes use of a voltage controlled oscillator (38)--VCO--to generate synchronism pulses (54) from the driving current generator (33), the controlling voltage being obtained from the comparison between the driving current and voltage phases through the resonant tank made up of the sensor (11) and capacitor (17) connected in parallel. The circuit further provides an amplitude limitation of the driving signal through the control of the driving current pulses applied to the inductive sensor.

Abstract: The reading head having the capability of processing two different data cards of the inductive type and chip-cards provided with contact pads on their surface. The raising and lowering of connection pins which contacting the pads is achieved by linking the pin supporting plate to rocking C-shaped driving arms having bifurcated free upper ends slidingly coupled to pivots which are attached to the plate. The lower limbs of the arms extend parallel to the lower face of the upper part of the reading head, the limbs having bosses facing the lower face, the gap between the bosses and the face being roughly equal to the thickness of an inductive card. The greater thickness of a chip-card presses down the bosses bringing about a clockwise rotation of the C-shaped arms around a fixed shaft resulting in a lowering of the connection pins which touch the contact pads on the card surface.

Abstract: A reading head able to process both inductive debit cards and chip cards comprising two dissimilar complementary portions, the internal surfaces of the portions defining the channel housing the data card inserted in the head, the first portion (80) having inductive sensors (83) for the reading of inductive credit cells and the second portion (140) having a magnetic metal plate (142) which completes the magnetic circuit of the inductive sensors, as well as contact pins (162) engaging the terminal pads on the surface of the card. The portions remain normally kept apart by a first set of mechanical coupling devices (84, 85, 86, 88, 89, 93, 94, 95, 144) placed between the two portions, the opening thus provided being substantially wider than the thickness of the card, the mutual approximation of the portions being provided by the mechanical devices at the final part of the card's insertion travel.

Abstract: An improved debiting method for inductive prepayment cards is provided in which a credit card cell set is divided into sectors for collection purposes, all credits collected from a given sector are collected before the next sector is collected from, the sectors are accessed in a standard order valid for all cards, each sector is made up of a column of cells parallel to a longitudinal axis of the card, and the credit cells are always accessed from the card's internal transverse edge toward the external transverse edge, independently of the orientation in which the card has been inserted in a read/write head.

Abstract: A directional coupler is provided which has an appropriately dimensioned principle waveguide with a frequency dependent reactive boundary interior surface such that the principle waveguide is suitable to simultaneously: (i) support, without depolarization, effective propagation of first signals in a high frequency band at a HE11 mode with greater concentration of energy near the axis of the principle waveguide than near the interior surface and no effective propagation of first signals at any unwanted mode, and (ii) support, without depolarization, effective propagation of second signals in a lower frequency band at a EH11 mode having a greater concentration of energy near the interior surface of the principle waveguide than near the axis and no effective propagation of second signals at any unwanted mode.

Abstract: A transition device achieves transformation of the signal carrier mode of a continuous wave guide, into the hybrid mode, the corresponding mode for carrying signals in corrugated structures, by employing a tapered waveguide transition of circular cross-section having dual-depth circumferential slots in the interior boundary surface thereof. The transition device utilizes a mutual resonance property of the slots at the port which connects to a continuous waveguide to achieve satisfactory operation in two frequency bands. At the port which is connected to a corrugated horn, the quarter wavelength self resonance of the individual slots provides the desired hybrid mode under balanced hybrid condition in these two bands. A gradual transition of the electrical characteristics is achieved along the length of the transition device through an adjustment of slot dimensions.