Abstract: High resolution character generator for producing rows of characters to be scanned on a display medium. Input data defining characters to be printed in ordered rows of text is sorted to provide specifications for the characters which being on each successive scan line. These specifications are stored initially in an input buffer, and specifications for characters which have been partially printed in a previous scan line are stored in an active character buffer. For each scan line, the character specifications are read first from the active character buffer and then from the input buffer until an end of line specifier is reached. For each character specification received, a font memory containing data defining the characters is cycled. The data from the font memory is decoded and presented to the display medium on a line by line basis.

Abstract: A heterojunction diode laser which achieves transverse mode control by providing adjacent to the active region layer of the laser a layer having a thickness substantially less than the thickness of the active region layer and of a material having a bandgap higher than the bandgap of the material of the active region layer. All transverse modes have increased penetration into a lossy substrate via the thin layer with the loss being least for the lowest order mode such that only the lowest order mode can be made to lase at low pumping current levels.

Abstract: A processing system adapted to control a sequential automated device to a state determined by the immediately preceding state. The system comprises a read only memory (ROM) (or alternatively a static RAM) having coded at each address in bit positions 2 through n the address of either the output signal to be controlled, the input signal to be sensed or the next ROM address. Bit position 0 indicates whether an output or input is to be selected and bit position 1 either determines the desired state of the input that is selected or routes the 2 through n bit position address to select the output or to set a new address for the ROM. Accordingly bits 0 and 1 from the ROM are combined with the selected input in a logical circuit comprising gates and inverters to either increment the ROM address buffer or jump to a new address.

Abstract: An optoelectronic device comprising a light-sensitive device which produces or modifies an electric current in dependence upon the intensity of light incident thereon, and a light-emitting device arranged to emit light in response to said electric current and so disposed that part of said emitted light is incident upon the light-sensitive device to provide positive feedback.

Abstract: A hammer protection circuit automatically disconnects a power supply from a hammer actuating coil in order to inhibit current flow through the coil when such current flow is either greater than a predetermined level or present for greater than a predetermined time period. The circuit comprises charging means coupled to the coil for charging up to a voltage level proportional to the level and duration of the current flow through the coil, comparator means coupled to the charging means for comparing the voltage level with a reference voltage and for generating an output signal when the voltage level bears a predetermined relationship toward the reference voltage, and means coupled to the comparator means and to the power supply and responsive to the output signal for disconnecting the power supply from the coil.

Abstract: Apparatus for segmenting a buffer memory into two-dimensional sectors such buffer memory having stored herein, in scan-by-scan format, bits representing the image of a document. The sectors comprise sections of adjacent scan lines arranged in a two dimensional array. Included in the apparatus is an address generating means which provides the address arrays for such sectors during the segmenting sequence and an encoding means which inspects the data in each segment. In the instances where all of the data in one sector represents background image a single bit code is transmitted. In all other instances the sector data is transmitted in its entirety. The same address generating and encoding means can be utilized in the receiving mode to reconstruct the code into corresponding data arrays to thus provide an image.

Abstract: A heterojunction diode laser which utilizes leaky wave coupling through a thin confining layer or a pair of thin confining layers to produce a high powered, highly collimated output beam with high external differential quantum efficiency, and relative freedom from facet damage resulting from high optical density.

Abstract: Apparatus for enabling communications between two or more data processing stations comprising a communication cable arranged in branched segments including taps distributed thereover. Tied to each tap is a transceiver which on the other side connects to an associated interface stage. Each transceiver includes, in addition to the usual transmitter and receiver sections, a gate which compares the data from the interface stage with the data on the cable and indicates whether such are equal. Should such be unequal, an interference between the transceiver and the cable is indicated, disabling the associated transmitter section. Each interface stage tied to such transceiver also includes an input and an output buffer on the other end thereof interfacing with a using device, such input and output buffers storing both the incoming and outgoing data.

Abstract: A phase-sensitive transducer apparatus comprises first and second relatively movable members, the first relatively movable member having a plurality of windings and the second relatively movable member having a winding. Means are included for applying a first input signal to one of the windings of the first relatively movable member and a second input signal to another of the windings of the first relatively movable member, an output signal being induced on the winding of the second relatively movable member. The first and second input signals are sinusoidal in nature of substantially identical frequency and peak amplitude and are phase-displaced by a predetermined amount, and the output signal is substantially constant in peak amplitude and variable in phase during relative movement of the first and second relatively movable members.

Abstract: A serial printer comprises a carriage, a print member rotatably mounted to the carriage and including a plurality of character elements, a drive coupled to the print member for rotating the print member to a desired rotational position, a device coupled to the print member for generating a plurality of periodic position signals each indicative of the rotational movement of the print member, and a device for storing a count indicative of the actual rotational position of the print member, the device for storing including a device responsive to an increment pulse for incrementing the count by one and a device responsive to a decrement pulse for decrementing the count by one.

Abstract: In a computer peripheral device having a controllable element and control means coupled to the controllable element and operative in response to a power supply voltage of a predetermined level for controlling the controllable element, an improved power supply means coupled to the control means for supplying said power supply voltage to the control means. The improved power supply means comprises a motor capable of being driven at a predetermined rate of speed, means coupled to the motor and responsive to the motor being driven at the predetermined rate of speed for generating the power supply voltage, and means coupled to the means for generating for supplying the power supply voltage to the control means.

Abstract: An analog chart recorder is provided having a heater assembly which includes a tapered, electrically resistive element that develops a non-uniform temperature profile on electrical energization along its length. A substrate is provided under the resistive film which is in thermal contact with the film. A heat sink in thermal contact with the substrate provides that the temperature distribution will achieve steady state. Means are provided for advancing a heat sensitive medium past and in contact with the heater assembly thus providing the analog chart recorder.

Abstract: A paper transport system used in connection with a thermal analog recorder is provided. This system engages the paper for a predetermined length of time and subsequently releases it employing mechanical means. Roller means are provided for engaging and transporting a heat sensitive paper. When the test paper is inserted into the nip formed between the roller means, a tapered resistor element residing on at least one of the rollers is made to develop a non-uniform temperature profile when energized from the output of a test source which permanently marks or records on the test paper. An improved method of single channel thermal analog recording is also disclosed employing this device.

Abstract: A head assembly for magnetic recorders includes a mounting bracket designed for increased rigidity. Releasably attached to the mounting bracket are two head carriages, each having affixed thereon a magnetic recording and reproducing head. The heads are positioned such that as the mounting bracket moves radially with respect to two recording discs, each head is individually precisely radially positionable with respect to any recording track defined on its respective disc.

Abstract: A matrix print head comprises stylus guide means; a plurality of electromagnetic structures coupled to the guide means, each of the electromagnetic structures including a pole piece; a plurality of armatures disposed radially about the guide means, each of the armatures being associated with one of the electromagnetic structures to form an electromagnetic actuator for transferring electromechanical energy to a stylus, and each of the armatures having an inner end and an outer end projecting outwardly of the associated pole piece; a plurality of styli respectively associated with the plurality of armatures, each stylus being carried by the guide means and having an armature engaging end for engaging the inner end of the associated armature and a printing end for impacting a record medium when the stylus is propelled through the guide means by energization of the associated electromagnetic actuator; and an improved armature retainer coupled to the guide means for maintaining each armature in engagement with its

Abstract: A linear actuator for selectively moving a carriage relative to a support frame along a predefined linear path.

Abstract: Method and apparatus for expanding the number of grey scale values in a digital flying-spot scanning system. The scanned recording medium is divided into a plurality of unit cells, each of which is assigned a desired grey scale value, and each unit cell is further divided into a plurality of subcells formed by a plurality of adjacent portions of scan lines comprising digitally controlled segments. The grey scale value of the unit cell is dependent upon the portion of the subcells within the unit cell which are activated or deactivated by the scanning beam. Additionally, the number of grey scale values between particular numbers of activated subcells is expanded by providing varying patterns of predetermined numbers of subcells within the unit cell with the varying patterns producing the optical effect of varying grey scale levels.

Abstract: A carriage assembly for transporting a print member along a predetermined path adjacent a support member comprises a first carriage section adapted to be mounted adjacent the support member for movement along the predetermined path, apparatus for mounting a print member to the first carriage section for movement between first and second positions relative to the support member, and apparatus coupled to the mounting apparatus for retaining a print member mounted to the frame in each of its first and second positions. The retaining apparatus includes a biasing member for biasing the print member in a direction opposite its second position when at its first position and in a direction opposite its first position when at its second position. The biasing member preferably includes an over-center tensioned spring coupled between the first carriage section and the mounting apparatus.

Abstract: A phase-sensitive transducer apparatus comprises first and second relatively movable members wherein the first relatively movable member has a plurality of windings and the second relatively movable member has a winding. Means are included for applying a first input signal to one of the windings of the first relatively movable member and a second input signal to another of the windings of the first relative movable member. An output signal is induced on the winding of the second relatively movable member. The first and second input signals are sinusoidal in nature of substantially identical frequency and peak amplitude and are phase-displaced by a predetermined amount, and the output signal is substantially constant in peak amplitude and variable in phase during relative movement of the first and second relatively movable members.

Abstract: An electrically pumped distributed feedback grating coupled diode laser having an optical cavity containing two closely spaced layers, a first of the layers is electrically pumped and the second of the layers is corrugated. Optical wavelength radiation and amplification of said radiation is generated in the first layer by carrier recombination with the radiation spreading to the second layer for coherent reflection by the corrugation and for low loss transmission. Carrier confinement in the first layer and optical confinement in the optical cavity are achieved by surrounding each of these layers by materials having a higher bandgap and lower index of refraction than the materials of the first and the second layers. The corrugation of the second layer can extend over only a portion of the length of the second layer such that the uncorrugated portion of the second layer provides a low loss waveguide.