Abstract: A method for coating the interior of a cylindrical surface comprising depositing on the interior or a rotating cylindrical surface a dry hydraulic cement composition and applying to the dry cement coating which is held stationary on the interior cylindrical surface by the centrifugal force of the rotating cylinder an aqueous composition and allowing the cement to harden to provide a coating having no tendency to slump or sag in the wet condition.

Abstract: A magnetic head reads data from reference zones on tracks at differing ra of a magnetic memory disc rotating at constant angular velocity. Each track includes at least one reference zone, each of which includes a plurality of initial cells. Each cell has magnetic flux variations, which when read by the head result in a first waveform that includes undulations enabling the head to be properly servo controlled to a position over the center of the track and a further undulation that is distinguishable from the head positioning undulations. The initial cells are followed by plural binary bit representing data cells each having magnetic flux variations which when read by the head result in a second waveform including a data representing undulation that is generally the same amplitude as the further undulations. The undulations are susceptible to having varying amplitudes as the head is positioned at different positions of the disc. The peak amplitude of the further undulations, for one reference zone, is detected.

Abstract: A separately excited constant load DC electric motor is controlled in resse to a source of current for the desired motor speed. Current from the source applied to the motor armature is modified by a motor loss simulator circuit responsive to the source. The circuit simulates the losses the motor is expected to have in response to the current derived from the source, whereby the actual motor speed corresponds with the desired motor speed despite the loss. The losses are simulated during acceleration and deceleration as well as steady state intervals of the current source, which can be actuated to drive the motor in both directions.

Abstract: A portable data or information carrier in the form of a card or the like. In order to maximize the confidentiality of information stored in the carrier, and more specifically to limit the amount of information available to a would-be defrauder monitoring data lines connecting the data carrier to external devices, the data carrier includes a microprocessor and an operatively associated protected memory to which access is protected. The memory includes at least one key or code which is compared to a key received from a device external to the data carrier to determine whether a particular operation is authorized. To ensure that the data carrier consumes the same amount of current whether the requested operation is authorized or unauthorized, the data carrier includes "access" and key "error" memory elements of the Electrically Alterable Read Only Memory (EAROM) type, and a bit is stored in the respective memory element in either event.

Abstract: A drop generator for an ink jet printer comprises a mechanical vibration amplifier which is adapted, when set in vibration at one end, to cause at least one ink jet emitted from its other end to break up into drops. An electromechanical converter device is fitted at said one end to impart a vibratory movement to the amplifier when it is excited electrically. A compensating block is attached to the electromechanical converter device so as to set up in the latter a nodal vibration zone. A support member holds the generator in position in the printer and the part of the support member which is in contact with the generator is situated in the nodal zone.

Abstract: A carrier for magnetic data recorded therein by perpendicular recording comprises a non-magnetic substrate having at least one substantially plane surface provided with a magnetic data layer of an anisotropic magnetic material having its axis of easy magnetization perpendicular to the said plane surface, and includes an additional layer of an anisotropic magnetic material whose axis of hard magnetization is parallel to the said plane surface. An intermediate non-magnetic, insulative coupling layer may be provided to maximize magneto-static coupling between the layers while minimizing energy exchanges therebetween. A further non-magnetic sub-layer may be provided directly on the plane surface of the substrate to assure good adhesion of the additional layer to the substrate and isolation thereof from the magnetic layer.

Abstract: A positioning system for electrical components to be mounted on a carrier includes establishing a first reference system and bringing the carrier on which the components are to be mounted to a predetermined position in relation to the first system. The locations for the articles to be mounted on the carrier are defined. A second reference system is established with respect to the first reference system and the carrier is positioned in relation to the articles to be mounted on the carrier using the second reference system. Each reference system is defined by at least three fixed points against which the carrier comes to bear and the points of the second reference system duplicate the points of the first reference system so that the carrier is in the exact position to enable the components to be mounted at the exact predetermined location.

Abstract: A tensioning device for materials of tape form particularly adapted for metic printers and comprises a floating element situated between free sections of a paper tape installed in return fashion in a driving mechanism. The floating element is provided with displacement transmission elements formed by spiked belts of which the spikes are engaged in perforations in the tape. The tensioning of the tape is provided by a weight hooked to the floating element such that the tape section emerging from the driving mechanism is driven, via the floating element, by the tape section which enters the driving mechanism.

Abstract: Data, in the form of a sequence of binary bits of frequency F.sub.O, is detected by deriving a clock signal H of frequency F.sub.O in response to the sequence. A level transposing device responsive to the sequence and signal H derives a bi-level signal DEI. An integrating apparatus responds to DEI to derive a signal DEINT. A decision circuit responsive to DEINT determines the polarity of signal DEINT and derives binary data bits having values that are a function of the polarity. The direction and duration of charging current supplied to a pair of capacitors of the integrator are controlled as a function of the polarity and duration of each of the levels of signal DEI, so the capacitors are respectively charged in response to even and odd numbered bits. The integrator is reset to zero at the end of the integrating operation for each level and the capacitive integrating member is supplied with a charging current proportional to F.sub.O.

Abstract: A ramp-launched read/write device for a data carrier includes an arm, a loading spring having a part fixedly connected to the said arm and a free end part, a platform incorporating at least one read/write transducer, a carrier member to carry the platform, and a guide member for controlling the position of the platform in relation to the data carrier. The guide member is made up of a level surface and at least one ramp, and is arranged to cooperate with the said guide member for bringing the platform to a first, rest position and a second read/write position close to the data carrier to allow the data carrier to be read from or written on. The carrier member includes a suspension spring which has one end fixedly connected to the arm and a free end adapted to contact with the platform. The guide member is fixedly but flexibly connected to the arm and the said free end part of the loading spring contacts the guide member in accordance with the positions of the platform.

Abstract: An arrangement for both exchanging data between first and second devices and supplying power from the first to the second device, all through only two interconnecting lines or contacts. Data transmission from the first to second device is accomplished by a modulated current generator in the first device connected to the two liens. Data transmission from the second to the first device is accomplished by a modulator which shunts the two lines while the current generator supplies a current, thus varying the voltage across the line in a manner which may be sensed by a comparator in the first device. In order to supply power to the second device, the second device includes a network having at least one unidirectional conduction member, such as a diode, connected to the two lines.

Abstract: A data processing system which protects the secrecy of confidential inforion includes a data processing machine with which an operator may carry on a confidential dialogue through a data transmitting device such as a keyboard and an auxiliary device in which is stored a predetermined permanent code key which controls access to the machine upon comparison to and recognition of a confidential code personal to the user. The auxiliary device may take the form of a card having an electronic integrated circuit means thereon and a plurality of contact members which are respectively connected to the circuit means by integrated connections. The contact members are designed to generate in response to external contact by a user operated stylus, a set of basic items of information corresponding to the confidential code personal to the user.

Abstract: An apparatus for transferring data blocks of variable lengths between intaces of different widths. The apparatus includes a series memory of the first-in, first-out type (FIFO) and an interface means at the input and output of the series memory. The interface means has a first means for storage of input data words and a second means for storage of output data words, the two storage means being of different storage capacity. Means are included for signalling to external devices when the first storage means and the series memory are empty and ready to receive data. Means are also included for controlling in response to an external signal the width of the output data words.

Abstract: Errors in reading data with a magnetic head from reference zones on tracks t differing radii of a magnetic memory disc rotating at constant angular velocity are determined. Each track includes at least one reference zone including a plurality of initial cells. Each initial cell has magnetic flux variations which when read by the head result in a first waveform that includes undulations enabling the head to be properly servo controlled to a position over the center of the track and a further undulation that is distinguishable from the head positioning undulations because it has a larger amplitude. The initial cells are followed by plural binary bit representing data cells each having magnetic flux variations which when read by the head result in a second waveform including a data representing undulation that has approximately the same amplitude as the further undulations. The undulations are susceptible of having varying amplitudes as the head is positioned at different positions of the disc.

Abstract: A memory of the MOS N channel type comprising two half-memories each conting the same number of columns, each column being bisected at the center by a refreshing amplifier. A bus is alotted to each half-memory and is connectable to any half-column in the half-memory which is addressed so as to read and rewrite in the refreshing phase. The extracting and rewriting arrangement incorporates a flip-flop having its inputs connected to the buses by a differential circuit and its outputs connected to inputs of a read and rewrite circuit. The buses are initialized at a low potential and a reference potential is applied to one bus when the other bus is connected to a half-column. Transient interference rise on the selected bus above the disturbance threshold of the refreshing amplifier is prevented.

Abstract: According to the present invention, a flat package for at least one integed circuit device having output pads comprises a supporting member for the IC device, a plurality of output terminals external to the package, an array of conductors connecting the said output terminals to the said output pads of the device, and a protective means. The supporting member is a wafer and the output terminals of the package are contact islands arranged on the said wafer. At least those conductors belonging to the array which are attached to the said contact islands rest on the said supporting wafer, and the protective means comprises an electrically insulating encapsulation which partly covers the supporting wafer and which leaves exposed at least the contact islands.

Abstract: A platform for supporting at least one magnetic transducer for reading from and/or recording on a data carrier. The platform is supported from a carrier arm adapted to position the platform over the data carrier which may be a multi-track disc. The magnetic transducer is supported in the lower face of the main body of the platform. The lower face includes a plurality of skids and one or more grooves which receive a rigid strut for suspending the platform over the carrier. The strut is secured in the groove (s) with the plane of the strut passing through the centers of gravity of the platform. The strut may be secured to a frame surrounding the platform which in turn may be secured to a further concentric frame also surrounding the platform.

Abstract: A platform for supporting at least one magnetic transducer for reading from and/or recording on a data carrier. The platform is supported from a carrier arm adapted to position the platform over the data carrier which may be a multi-track disc. The magnetic transducer is supported in the lower face of the main body of the platform. The lower face includes a plurality of skids and one or more grooves which receive a rigid strut for suspending the platform over the carrier. The strut is secured in the groove(s) with the plane of the strut passing through the center of gravity of the platform. The strut may be secured to a frame surrounding the platform which in turn may be secured to a further concentric frame also surrounding the platform. The strut includes a constriction located at the virtual axis of rotation or axis of oscillation of the platform and at which point the cross-sectional area of the strut is at a minimum.

Abstract: A microinstruction address is determined in response to the content of an mediately preceding microinstruction. A data processing apparatus contains a memory for storing microinstructions at addressable locations. Testing bits are loaded into a test register while a microinstruction read from the memory is loaded into a microinstruction register.

Abstract: An architecture for a special purpose microprocessor particularly adapted for coupling a computer to its associated peripheral devices or to transmission lines. To minimize restrictions on the speed of data exchange, the present microprocessor allows the following to take place simultaneously: (1) general coupling of the computer and associated transmission lines and, more particularly, execution of instructions for coupling, shifting, or indirect conditional branching; and (2) the performance of arithmetic and/or logic operations on data which is exchanged between the computer and the associated transmission or peripheral lines. The present microprocessor executes microinstructions which are stored in a control memory. The format of the microinstructions is such that information in various zones controls the functions to be simultaneously performed.