Abstract: A phase-locked oscillator (PLO) driven or derived clock system, the frequency of which is higher by a factor N than the frequency of the bit reference clock of incoming streams of data bits. The derived clock is designed to be maintained in synchronism with the bit reference clock. Two counters are provided, both of which are driven by the derived clock. The reference counter counts to N/2 and outputs a pulse. The other counter counts to N, outputs a pulse and starts again. The two counters provide output pulses which are coincident whenever the derived or PLO clock is in synchronism with the data clock. This is determined by a phase detector which includes a pair of identical latches, each of which is set by one of the two counters. The outputs of the latches go to an AND gate, the output of which resets the latches. The outputs on the two Q leads from the latches go to an amplifier which outputs a signal which is other than zero, only when there is lack of synchronism.

Abstract: A tape deck providing means to drive and control a file reel and a machine reel including a vacuum source and a capstan drive means, the tape deck including a first vacuum column of relatively wide width and short length extending upwardly and at an acute angle to the vertical plane encompassing the axis of the file reel and machine reel, and a second relatively wide, short length vacuum column below the first vacuum column and having an axis intersecting the axis of the first vacuum column at an acute angle, the second vacuum column having a transverse end wall at an angle to the second vacuum column outer wall, the sources of vacuum being applied to the vacuum columns, the capstan being positioned at the entrance to the second vacuum column so that a short length of tape extends from the capstan to the exit of the first vacuum column, the tape being wrapped 180.degree.

Abstract: An apparatus for calibrating the gain in a tape drive read system, so that with a calibrated signal source, the output of the read system will be a clean, square wave, digitized signal. Means are provided for taking the output of a read head, reading signals from a tape, applying a controlled attenuation to the signals, such that the output of the read system will be of a correct amplitude output. A sensor assembly including a comparator, is used to monitor the output voltage from the read system, and to provide appropriate signals to the attenuator until the analog output voltage of the read signal is correct.

Abstract: A drive for a magnetic tape including a tape deck, a skew plate having an opening in each end thereof for attachment by means of screws to the face of the tape deck, one of the openings being internally threaded, a read/write head affixed to the skew plate between the openings and having a longitudinal read/write surface thereacross engageable by a magnetic tape, the longitudinal read/write surface extending generally perpendicular to the skew plate rearward surface, a cup screw received in the threaded opening in the skew plate, the cup screw having an opening through it receiving one of the screws by which the skew plate is held to the tape deck, whereby the angle of the skew plate relative to the tape deck and thereby the angle of the read/write head relative to the path of tape across it, can be adjusted by rotational adjustment of the cup screw.

Abstract: Apparatus is provided for converting serial bit digital signals of selected line rate from a plurality of sources into a single serial bit signal for time division multiplexing (TDM) in periodic frames by a central receiver, in a system in which each source is responsive to command signals for transmitting signal information to the receiver.

Abstract: A reel hub latch for use in holding rotating devices, such as a reel of tape, rigidly and concentrically to a rotating shaft, in which a seating surface is provided for the reel on the outside surface of a first or hub portion of the device. There is an annular channel in the outer surface of the hub in which is provided a ring of deformable material, which has two parallel faces perpendicular to the axis of the ring. These two surfaces are provided with shallow narrow ridges molded into the material which are equally spaced around the circumference of the ring. The walls of the annular channel are likewise provided with an equal plurality of shallow narrow grooves in the parallel facing walls of the channel. A segmented disk is provided in the hub to extrude the deformable material outwardly with the movement of the handle, and to withdraw the ring material into the channel when the handle is moved in the reverse direction.

Abstract: An ADM codec includes CVSD encoder and decoder circuitry having a syllabic filter responsive to the binary state of the ADM bit samples for changing the quantization step amplitude at a rate of change directly proportional to the rate of change of slope of the received voice signal.

Abstract: A capstan for use on a tape transport, including a hub, a tubular outer rim supported co-axially about the hub, and a body portion of foam plastic between the hub and rim.

Abstract: A state clock provides a bilevel signal of frequency which is an even multiple of the frequency of an incoming digital signal. A plurality of latches are responsive to the state signal. The outputs of the latches go to corresponding inputs of a memory array, the outputs of which are a plurality of terminals equal in number to the binary bits of a word stored in each address of the memory array. One of the output leads of the memory array passes through one of the state latches and to the output circuit. The other outputs go to the state latches where they are stored temporarily. The state latches are set on the rising transition of the state clock, while an input signal latch is set on the falling transition of the state clock.

Abstract: An electronic switching system for inductive loads in A.C. circuits, comprising a triac switch in series with an inductive load such as transformer or motor, etc. across an A.C. voltage. The control voltage for the triac switch is provided by a smaller, lower power triac driver, which has a light emitting diode controlled by an optically isolated transistor. The optically isolated transistor is provided with electrical pulses each a half cycle of voltage by means of a zero crossing detector. Since it is impossible to know precisely what the power factor of the load is, the triggering of the triac driver is provided at zero voltage on both the upward and downward crossing. These pulses, amplified by the transistor, control the triac driver. The load current will lag the voltage by some angle, dependent on the power factor, and the current will stop at its zero point.

Abstract: A ribbon cartridge for use in high speed cartridge type printers, in which the ribbon is enclosed in the cartridge, and the entire cartridge must move at extremely high speeds. The cartridge is in a generally U-shaped case with the base of the U comprising a ribbon storage volume. One of the arms of the U is called the exit arm, and the other called the re-entry arm. Positive pressure roller means is provided for driving the ribbon into the storage volume, thereby pulling ribbon out of the storage volume at the other end, out through the exit arm where a pad of felt, or the like, is used to provide suitable tension. The ribbon then moves across between the two tips of the U arms, down and into the re-entry arm. An ink reservoir is provided in the re-entry arm, comprising a wedge of felt or similar material and including means to apply marking fluid, such as stamp pad ink, to the wedge.

Abstract: An improved capstan for a tape drive of the type for attachment to the shaft of a drive motor, the capstan being formed of a body having low mass and providing a cylindrical tape engaging surface and means for axially securing the body to a motor shaft. The capstan body has a radial sidewall. A thin disc of a diameter no greater than that of the capstan is secured to the radial sidewall by a layer of compliant adhesive. The layer of adhesive serves to provide resilient energy-absorptive rotation movement between the capstan body and the disc to reduce the effect of capstan resonance.

Abstract: A tape drive hub having an improved reel latch, a hub body having a plurality of radial openings communicating with a reel receiving cylindrical surface, a tapered locking member carried axially by the body removable from an unlocked to a locked position, and an actuator received in each of the radial openings, each of the actuators being formed of a cylindrical body having a piston at the outer end and means at the inner end for engaging the locking member, and each actuator cylindrical body including a preloaded spring engaging the piston so that when the locking member is axially advanced into the locked position, each cylindrical body is pushed outwardly to engage the piston end with a reel positioned in the hub, the force of engagement being determined by the preload on each of the actuator springs.

Abstract: A capstan for use on a tape transport, including a hub, a tubular outer rim supported co-axially about the hub, and a body portion of foam plastic between the hub and rim.

Abstract: An automatic, pneumatic reel latch, comprising a hub adapted to be attached to a drive shaft of a tape deck, the hub has an annular groove forming an inner cylindrical surface and an outer thin cylindrical shell. A cup-shaped piston is fitted with a rolling diaphragm and inserted into the groove. A plurality of tapered flats are molded on the outer surface of the piston. Compressed air is supplied through an axial bore in the drive shaft, into the cylinder, causing the piston to move out of the groove, and by cam action of the lands, move outwardly a plurality of roller friction pad assemblies, having friction pads on their outer surfaces. A tape reel is adapted to slide over the latch and to be outside of, and co-planar with, the friction pads. The pneumatic pressure of the piston will force the friction pads into contact with the reel, providing sufficient friction to drive the reel in synchronism with the hub.

Abstract: A power-on-reset circuit with power fail detection, comprises a supply voltage V, and a voltage divider comprising two series resistors connected between V and the ground. The junction between the two resistors is connected to the (+) terminal of a voltage comparator. The junction is also connected through a diode to the (-) terminal of the comparator. The (-) terminal is also connected to ground through a capacitor and resistor in parallel. A resistor and compacitor in series are connected between V and ground and the junction between the resistor and the capacitor is connected to the output of the comparator, and also to the input of an inverting gate. The output of the inverting gate is the power-on-reset terminal.

Abstract: Apparatus for removably supporting and electrically grounding a cover to a base structure, having an upper and lower attachment assembly, the lower assembly having a hanger with a horizontal portion and an integral vertical portion, a leaf spring of inverted V-shaped configuration with a vertical leg affixed to the base structure and an angular leg extending to normally resiliently engage the hanger vertical portion, a lower bracket affixed to the cover having a horizontal leg and an integral vertical portion at the leg outer end, the horizontal leg having an opening to receive the hanger vertical portion, the upper assembly having a hanger with a horizontal portion with an opening therein, a leaf spring of inverted V-shaped configuration having an angular leg extending downwardly through the opening, and an upper bracket affixed to the cover having a downward extending vertical portion, the upper and lower hangers engaging the upper and lower brackets and the springs of the upper and lower hangers being resi

Abstract: In a dual stage power transistor type amplifier in which a video signal is applied to the base of a first stage transistor and in which the output of the first stage is direct coupled to the emitter of the second or power stage, and in which the second stage has a substantially constant d.c. voltage applied to its base, and a higher constant d.c. voltage applied to its collector through a load impedance. A voltage limiting device such as a Zener diode is shunted across at least a portion of the load impedance. With the fixed voltage on the base and a limited d.c. voltage on the collector, saturation and overload of the transistor is prevented.

Abstract: Apparatus for filtering high frequency noise pulses from alternating analog data of a frequency F, which includes means to convert the analog signal to a square wave bi-level signal, sampling the square wave signal at a clock frequency of at least 8F, loading the sampled signals into a digital shift register at the clock rate, reading out in parallel at least the last three samples, and passing said samples to a majority gate, which outputs a signal representing the majority polarity of the three signals read. The output of the majority gate is then applied to a latch in synchronism with the clock signal, which converts it back to a square wave signal representing the noise filtered version of the input signal.