Abstract: An optical transducer has an optical head mounted above an optically encoded reflective disc. Broad band radiation is supplied to the head via a single fibre cable. This head is a solid glass block with a curved reflecting surface that collimates and reflects radiation onto a diffraction grating. Radiation is dispersed by the grating and reflected back onto the curved reflecting surface. This causes the radiation to be focussed onto the disc as a spectrum. The head combines radiation reflected from the disc and focusses it onto the end of an output fibre. A wavelength decoder at the other end of the output fibre disperses the received radiation so that an array of photodiodes provides an output representing the location of the reflective parts of the disc from which the position of the disc is determined.

Abstract: An acousto-optic scanner comprising at least two optical sources the outputs of which differ in frequency, a common acousto-optic deflector, a scan lens, and scan correction means. The output of the light sources are directed through the common acousto-optic deflector and the outputs of the common acoustic-optic deflector are directed through the scan correction means which comprises a plurality of optical elements. The effect of the optical elements on optical beams is dependent upon beam characteristics.

Abstract: Defining the structuring of bubble domains in a magnetizable layer of a bubble domain memory plane is determined by modifying the magnetic characteristics of the magnetizable layer in the confinement area. The bubble domain memory plane is comprised of a non-magnetic Gadolinium Gallium Garnet (GGG) layer which is a supporting layer upon which is formed by the liquid phase epitaxy (LPE) method a plurality of magnetizable layers in each of which a bubble domain is capable of being generated and sustained. Upon the memory plane are formed, as by any of many well-known deposition techniques, a matrix array of a parallel set of horizontally oriented X drive lines and an orthogonally oriented parallel set of Y drive lines. Each X drive line, Y drive line intersection of the matrix array defines a memory area having four quadrants.

Abstract: Disclosed is an apparatus for and a method of propagating bubble domains along fixed guidance channel forming stripe domains by capturing them in moveable stripe domains and then moving the capturing moveable stripe domains. The memory plane comprises a non-magnetic Gadolinium Gallium Garnet (GGG) layer which is a supporting substrate upon which are successively formed by the liquid phase epitaxy (LPE) method: a first stripe domain layer, a first non-magnetic spacer layer; a bubble domain layer; a second non-magnetic spacer layer; a second stripe domain layer; and a third non-magnetic spacer layer upon which is formed the necessary propagation circuitry.

Abstract: A lung ventilator which transmits from a bellows respirable gas and/or anaesthetic gas directly to a patient during the inspiratory phase of the patient's breathing cycle and in which, during the expiratory phase of said cycle, the patient exhales directly into a rebreathing bag and at some time during this latter phase, the bellows is caused to inflate to thereby draw in exhaled gas both directly from the patient and from the interior of the rebreathing bag. The bellows and rebreathing bag are isolated one from the other by a biassed flow control valve situated in a conduit linking them together, which valve will allow the contents of the rebreathing bag to be emptied into the patient by squeezing the bag at any time during operation of the ventilator.

Abstract: A method of and an apparatus for improving the selective positioning of single wall domains or bubbles in a memory system is disclosed. The method includes the use of slotted intersecting digit and word lines that are coated with a magnetic material of relatively high retentivity.

Abstract: A method of making an oxide isolated integrated circuit structure is simplified by forming a first level metallization pattern without the conventional underlying insulating layer and without the need for restricting the size of the metallization to the size of the semiconductor regions to be contacted. Portions of the first level metallization pattern can extend on the oxide isolation region to contact two otherwise isolated semiconductor zones. Additionally, subsequent to the formation of the oxide isolation regions and the first level metallization, an intermediate dielectric masking pattern is formed so the combination of the first level metallization, the oxide isolation regions and the masking pattern defines zones for the introduction of impurities. Further, the masking pattern alone is used to provide contact holes for a subsequently formed second level metallization pattern.

Abstract: A telephone amplifier circuit comprising a transmit amplifier and a receive amplifier provides gain in both the transmit and the receive directions. Loss is voice-switched into the receive amplifier in response to the sum of the transmit and receive speech levels to provide sidetone and gain control.