Abstract: A phase lock system for locking the output pulses of a motor driven tachometer in phase with reference pulses that recur at a prescribed reference frequency. A phase/frequency detector operates in a frequency mode when there is a frequency difference between the output pulses and the reference pulses so as to generate an error signal indicative of the frequency difference and a saturating amplifier coupled between the phase/frequency detector and the tachometer motor responds to the error signal to provide maximum drive power to the motor so as to vary the tachometer and drive the output pulse frequency toward the reference pulse frequency at a maximum rate. When frequency equality is achieved, the phase/frequency detector operates in a phase mode in which the phase error between the output pulses and the reference pulses is measured at a time when the system is still in saturation because of its high gain.

Abstract: A circuit for discriminating among pulses in a series of recurring pulses based on the interval between adjacent pulses which circuit is particularly useful in extracting timing information from a series of pulses such as are induced in a servo head by movement relative thereto of a prerecorded servo track in a disc pack data storage system. The circuit includes a monostable multivibrator for producing a timing signal having a duration corresponding to the time interval between two successive pulses. The monostable multivibrator output is stored, for example in a data flip flop, so as to produce an output pulse from the flip flop if a succeeding pulse in the series occurs while the monostable multivibrator output is high.

Abstract: A servo system for accurately positioning a transducer relative to data paths on a recording medium by detecting sync and servo signals from two parallel abutting servo tracks sharing a common longitudinal boundary within circumferentially spaced sectors of the medium. Within each sector of the recording medium, two servo waveforms of different frequencies in two abutting servo tracks are preceded by a sync reference waveform of the same frequency in both servo tracks which is used as a reference for a phase locked oscillator, connected to the transducer, generating a pair of modulation signals that are to be mixed with transducer signals from both servo waveforms. A pair of servo channels are provided for receiving the pair of modulation signals and the servo signals for deriving an imbalance error signal representing deviation of the transducer from the center line of a data path, which is the projection from the sectors of the common longitudinal boundary between servo tracks.

Abstract: An electronic tachometer comprising an integrator having its output coupled to a variable gain amplifier and responsive to an input signal representative of the acceleration of a moveable load, such as a head assembly of a disk drive, for producing a coarse velocity signal at the output of the variable gain amplifier indicative of the load velocity, a tachometer gain correction circuit including another integrator coupled to receive the coarse velocity signal to produce a coarse distance signal indicative of distance traveled by the load and means for combining the coarse distance signal with a reference distance signal to produce a distance error signal which functions to adjust the gain of the variable gain amplifier so as to vary the coarse velocity signal to make the coarse distance signal equal to the reference distance signal, and accumulative error compensation means coupled to receive a gain indicative signal derived from the distance error signal to produce a signal input to the tachometer integrator

Abstract: A method and an apparatus for encoding and decoding a binary digital data signal is disclosed. An input signal that is to be encoded for transmission is shifted through a serial shift register with the bits in the stages of the shift register at each of the successive shift periods being used to define a binary coded addressable location in an associated memory. The memory has stored in each of its addressable locations a further binary code that when addressed by the shift register produces, as an output, a binary True or Complement signal which through a True/Complement generator couples the True or the Complement of the input signal to the transmission medium. The receiving end of the transmission medium has a similar arrangement of shift register, memory and True/Complement generator that decodes the received encoded transmitted signal.

Abstract: In the present device, a base member is included which has channels formed therein to hold lead wires. In the preferred embodiment a metal foil resistor member, having termination land sections, is secured to the base member to form a fourth side for each channel, thereby securely locating the lead wires in the channels and the lead wires are firmly connected to the termination land sections of the foil resistor. Accordingly with respect to the foil resistor assembly: there is good physical strength to withstand external forces; the resistor reliability is enhanced; the fabrication is simplified; and the resistance range capability is increased.

Abstract: Apparatus for generating elevation and azimuth reference signals for use in demodulating a tracking error signal to provide elevation and azimuth error components for use in adjusting the position of a tracking conical scan radar antenna, includes a template ring having a notched periphery and being attached to a rotatable nutator of the antenna such that its peripheral notches are in a predetermined angular phase relationship with a reference position on a feed horn attached on the nutator, during rotation of the feed horn with the nutator. The apparatus further includes an optical transducer and electronic circuitry coupled thereto for producing the reference signals from a signal generated by the transducer in response to rotation of the ring with the nutator. As the ring rotates with the nutator, its notched periphery makes or breaks a photon path between light beam generating and sensing elements of the transducer.

Abstract: Disclosed is a solid state apparatus for and a method of (1) modulating the intensity of a multimode light beam; (2) coupling the light beam to an input optic fiber that is butt coupled to a diffraction grating that is formed of a plurality of stripe domains in a magnetic film; (3) altering, by the application of suitable magnetic fields, the angular orientation of the stripe domains in the plane of the magnetic film, and (4) multiplexing the diffracted light beam to a selected one of a plurality of several output optic fibers. The apparatus uses a liquid-phase epitaxially (LPE) grown film of bismuth substituted rare earth iron garnet to form a magnetizable layer in which stripe domains may be generated, sustained and moved about. The stripe domains form a diffraction grating. The angular orientation of the stripe domains in the plane of the diffraction grating may be altered by the application of external magnetic fields.

Abstract: In a magnetic recording system having a medium for storing information in the form of encoded digital data, an improvement in the recording head control circuit including means and a method for determining the temporal occurrence of a major write transition of the encoded digital data and producing a minor write pre-transition and a minor write post-transition each having a lower amplitude and an opposite direction to that of the major write transition thereby providing a readout pulse corresponding to the combined write transitions having a narrower pulse width and improved symmetry which enhances the accuracy in reading out the recorded digital data and increases the packing density in the storage medium of the recording system.

Abstract: Electronic digital apparatus for computing an approximation of the arctangent of a given tangent number, N, being in the range of 0 to 1 and in binary form, operates in two stages to provide a solution of the expression: ##EQU1## During the first stage, steps are taken by the apparatus to find out where within the range of 0 to 1, divided preferably into four equal increments, the known tangent number N is located. When the correct increment represented by one of a plurality of increment numbers I.sub.j stored in a ROM unit of the apparatus is found, then one of a like plurality of center numbers C.sub.k of that increment also stored in the ROM unit may be readily selected, as can also be the corresponding one of a plurality of stored numbers A.sub.i representing the arctangents of the stored center numbers C.sub.k. During the first stage, the product number C.sub.k (N) is also formed. In the second stage of operation of the apparatus, the dividend and divisor numbers N-C.sub.k and 1+C.sub.

Abstract: The present device provides an air duct means disposed between the top end of the heat exchanger of a furnace and the entry port into the flue pipe of the furnace. An electrical blower means is coupled to said duct means to draw hot air therethrough which would otherwise go out to the atmosphere through the flue. The hot air drawn by the blower is redirected to heat, or assist in heating, the building to which the furnace is directing heat, or heat some other facility. An electrical control circuit is connected to the blower means and controls the blower means such that if the furnace is burning fuel, the blower cannot be turned on. The blower can only be turned on after a predetermined time has elapsed from the time that the fuel burning has terminated, so that combustion gases which otherwise would pass through the flue and which might contain harmful ingredients therein, will not be redirected to be used as a source of heat.

Abstract: A method of and an apparatus for reading out the information that is stored in a magnetizable layer that is formed of a thin film in which data are stored as inverted Neel wall sections about associated Bloch-lines along a cross-tie wall. The apparatus utilizes a magnetizable layer which is configured into a strip whose two opposing edges are, along its longitudinal axis, formed into mirror-imaged, spaced-apart, repetitive, asymmetrically-shaped patterns which repetitive patterns are formed of successive narrow portions that form wide portions therebetween. The repetitive patterns, when suitable magnetic fields are coupled thereto, form a cross-tie wall along the longitudinal axis of the strip while structuring the cross-ties along the cross-tie wall at the narrow portions and the Bloch-lines along the cross-tie walls and between the adjacent narrow portions.

Abstract: Multiple dial adapter to provide interfacing between a communications multiplexer module (CMM), such as a computer system, and a plurality of automatic calling units connected to telephone lines. The adapter permits control of the automatic calling units via a single computer port and time shares common logic of the computer. The adapter also provides the capability of easily programmed pauses of any desired length in dialing sequences as required when dialing through remote telephone exchanges such as tie lines.

Abstract: The present circuit controls the high current delivered to a load from a direct current (d.c.) power supply through a pair of power silicon controlled rectifiers (SCRS). For each power SCR there is also employed an associated current conduction control SCR. Each of the current conduction control SCRS acts, when triggered, to terminate the current conduction of its associated power SCR. Each current conduction control SCR is controlled by the provision of current thereto during conduction and non-conduction half cycles of an alternating current source, which operates independently of the d.c. power supply. Accordingly, the occurrence of a current (load) transient, even though it may provide an abundance of current to either of said power SCRS, will not prevent the termination of the current conduction of said power SCR for an excessive period after it should have been turned off.

Abstract: A data source is connected through a gating circuit to all stages of an asynchronous shift register. The gating circuit senses the full or empty status of each stage of the shift register and enters an incoming bit of data into that stage of the shift register which is the empty stage nearest the output, and has no stage preceding it which is full. The arrangement decreases the delay time normally encountered by data as it is shifted through the shift register, the decrease in delay time being related to the number of empty stages in the register at the time a bit of data is entered.

Abstract: An organization of serial-parallel-serial (SPS) charged-coupled-device (CCD) memory arrays or blocks into a memory system is disclosed. Each memory block is comprised of an N-bit input register, an N-bit output register, N S-bit parallel registers and an N-bit I/O register. Data is bit-serially entered into the input register at a frequency F.sub.0 is bit-parallelly shifted through the parallel registers and simultaneously into the output register and the I/O register at a frequency F.sub.0 /N. Addressed read data are captured by the I/O register and are circulated continuously therein independently of the recirculation process performed by the output register, input register such that if I/O transfer rates are lower than the allowable refresh frequency of the charged-coupled-devices of the memory block, and if one or more refresh cycles are utilized, the addressed read data always remains available in the I/O register.

Abstract: The present electrical resistor package has a naked electrical resistor element which is designed to provide quantitative resistance to electrical current flow, said element is initially encapsulated in a flexible coating, such as silicone wax, which absorbs stresses and is secondarily encapsulated around said flexible coating, in a cushion type moisture barrier coating, such as silicone rubber, to keep moisture away from said element and finally is encapsulated around said moisture barrier coating by a hard protective coating, such as epoxy, to protect the nak ed element from physical and environmental damage.

Abstract: A system of encoding a fixed-level character format for transmission in a format of variable or multi-level character lengths is disclosed. A fixed-level character format, e.g., an 8-bit character length of high to low ordered bits 2.sup.7 -2.sup.0, received by a transmitting communications line terminal from an associated processor at a transmitting site is examined, a "Short" bit 2.sup.S is generated, and depending upon the number of higher order bits that are 0 bits and whether the remaining bits are an odd or an even number of 1 bits, a new variable or multi-level character is generated and transmitted on the communications line along with the associated "Short" bit. The reverse procedure is utilized at the receiving communications line terminal to regenerate the fixed-level character format utilized by the associated processor at the receiving site.

Abstract: An apparatus for and a method of storing binary data in a thin ferromagnetic film strip as the presence or absence of Bloch-lines without the presence of cross-ties. The apparatus utilizes a serrated strip of isotropic magnetic material that is formed in the shape of a series of contiguous disks. Each pair of contiguous disks is coupled by a narrow section of magnetic material that functions as a "door" between adjacent disks through which the Bloch-line defining datum bit may be propagated when subjected to the appropriate drive fields.

Abstract: Disclosed is a solid state apparatus for and a method of (1) modulating the intensity of a multimode light beam; (2) coupling the light beam to an input optic fiber that is butt coupled to a diffraction grating that is formed of a plurality of stripe domains in a magnetic film; (3) altering, by the application of suitable magnetic fields, the angular orientation of the stripe domains in the plane of the magnetic film, and (4) multiplexing the diffracted light beam to a selected one of a plurality of several output optic fibers. The apparatus uses a liquid-phase epitaxially (LPE) grown film of bismuth substituted rare earth iron garnet to form a magnetizable layer in which stripe domains may be generated, sustained and moved about. The stripe domains form a diffraction grating. The angular orientation of the stripe domains in the plane of the diffraction grating may be altered by the application of external magnetic fields -- see the E. J. Torok, et al, U.S. Pat. No.