Abstract: A device for receiving dual polarized microwave signals, including a first waveguide connected to a receiving antenna and to a first substrate bearing a first sensor perpendicular to the longitudinal axis of the first waveguide, a second waveguide having the same longitudinal axis and the same dimensions as the first waveguide, and which is connected to a second substrate having a second sensor perpendicular to the longitudinal axis of the second waveguide. Surrounding the second waveguide is a tube having tongues at opposed ends which cooperate with slots formed in the first and second substrates. The opposed tongues of the tube are staggered by 90.degree. so that upon insertion of the opposed tongues of the tube within the slots of the first and second substrates, sensors formed on these substrates are arranged orthogonally with respect to one another. The tongues and cooperating slots assure mechanical integrity.

Abstract: The video image projection system of the invention includes two projecting devices formed by cathode ray tubes for projecting a green color onto a projection surface and two other projecting devices for projecting red and blue colors. The two green projecting devices project superimposed images. A circuit is provided for processing a video signal to supply a background signal without fine details to one of the green projection devices and a sharp contour signal to the other green projection device.

Abstract: The card is particularly intended to give a card-holder access to a service such as pay-TV (broadcast or cable), but in principle could be adapted to any lock-and-key type of system, e.g. credit cards, cards giving access to computer terminals or rooms, etc. The data is encoded on the card in the form of data-significant marks and spaces (2, 3). For example, the marks (2) may be distributed along two parallel tracks with marks in one track representing "1" bits and marks in the other track representing "0" bits. Dummy marks (20, 21, 30, 31, 32, 33) are also made on the card. The dummy marks have the same appearance to the human eye and to photographic and photocopying equipment as the data-significant marks. However, they are printed using inks having a different response in an invisible part of the spectrum, so that card reading equipment can be made to treat dummy marks differently from the way it treats data-significant marks. This makes the cards difficult to fake using commonly available equipment.