Abstract: A battery charging apparatus for charging a stack of multiple lithium ion battery cells charges the stack by a combination of switched capacitance cell balancing and cell voltage monitoring to provide a charge cycle that starts with a nominally constant current charging and easily shifts to constant voltage taper charging.

Abstract: Lithium polymer battery charger methods for charging a plurality of equal charge point lithium polymer battery cells prevent overcharging of any cell, whether the cells are arranged in a series stack or are arranged in parallel. When the cells are connected in a series stack, a power supply is connected to the series stack to apply a charge current to the series stack. The state of charge of each cell in the stack is monitored. Information that the state of charge of any cell is approaching full charge is used to control the charge current and to prevent overcharging of any cell.

Abstract: Lithium polymer battery charger apparatus for charging a plurality of equal charge point lithium polymer battery cells prevent overcharging of any cell, whether the cells are arranged in a series stack or are arranged in parallel. When the cells are connected in a series stack, a power supply is connected to the series stack to apply a charge current to the series stack. The state of charge of each cell in the stack is monitored. Information that the state of charge of any cell is approaching full charge is used to control the charge current and to prevent overcharging of any cell.

Abstract: A position servo system is described for positioning a member mounted on a spring. The spring provides a force opposing the motion of the member from an initial position. A position actuator, for example a motor, applies a force in response to a position request signal for moving the member to a desired position. A portion of the position feedback signal is applied from a position sensor to the motor as a positive feedback signal to compensate for the force of the spring. A steady state position error of the servo system is thereby substantially reduced to zero. A circuit and method for calibrating the positive feedback signal are also described.

Abstract: A disk drive that generates a smooth spiral during the recording of data so that the recording operation is continuous. A magnetic read/write head (2) is mounted on an arm (4) so that it can move generally along a radius of a disk (8). A rotary motor (12) is used to spin the disk and to drive a gear train. The output of the gear train is used to move the arm-mounted head across the disk. The pitch of the spiral generated is controlled by the relative gear ratio between the disk and the head mechanism. Rapid retrace of the head mechanism to its starting position is accomplished by placing a return spring (56) on the head mechanism and a clutch (42) in the gear train. The location of the clutch in the gear train is chosen so that the head mechanism, while being returned to the starting position under spring power, spins a neutral pitch fan (102). The energy dissipated by churning the air by the fan limits the peak velocity of the head mechanism.

Abstract: A disk drive having a head actuator that is capable of quick, fine adjustments in position of the transducing head in order to precisely follow data tracks. A magnetic read/write head (2) is mounted on a first arm (4) so that it can move generally along a radius of a disk (8). A rotary motor (12) is used to spin the disk. A primary motor (36) in conjunction with a cable (42) and drum (40) is used to move the arm-mounted head in coarse movements across the disk. A secondary motor (32) in conjunction with a second arm (34) is used to move the arm-mounted head in fine movements across the disk. The primary motor may be used for track jumping, while the secondary motor may be used for track following.

Abstract: A playback head (155) is moved across a recording medium (151) orthogonally to a data track by playback head-moving means (157, 159, and 161), said data track being independently moved so that previously-recorded data is sequentially recovered. An electrical signal, which bears a direct relationship to the velocity of the head-moving means, is produced by a position sensor affixed to the head-moving means and a differentiator (169). Said signal is used to close a velocity loop, through a summing junction (171) and a power amplifier (173), around the head-moving means. The playback head is moved in addition, at a relatively high frequency, by dithering means which causes an amount of head motion that is small with respect to the width of the data track. The dither motion causes an amplitude modulation of the signal being recovered from the data track by the playback head.

Abstract: A high-resolution, electronic camera with real-time storage capability. The image at the focal plane of a lens (5) is electronically scanned in one direction by a linear photodiode array (1), and in the orthogonal direction by a carriage (3), motor (17), and leadscrew (13) subassembly which mechanically moves the array with respect to the lens. The motion of the array is directly translated into comparable relative motion of a recording head (19) with respect to a recording media (21) so that scanned pixel information is recorded on the media (21) concurrently with its generation.

Abstract: An apparatus for the very precise centering of a flexible recording disk (2) onto a disk-drive spindle (8), for clamping it firmly for spinning, and for the easy removal thereof. Disk (2) is provided with a reinforced center hole (4) so that it can be manufactured to a tight tolerance. Spindle (8) is provided with a precision-alignment cylinder (12) over which the disk must slide in order to rest on a spindle seat (6). Once disk (2) is resting on spindle seat (6), it is clamped there by a self-aligning, rotatable spindle cap (24), which is brought down on top of the disk. The disk is centered for sliding along the alignment cylinder through the action of a conical surface on cone (14). The cone (14) in its entirety may be part of spindle (8), or alternatively, in order to facilitate insertion and removal of the disk, part of the cone may be integral to the clamping-spindle cap (24), or be a retractable plug.

Abstract: Apparatus for automatically producing microfiche from microfilm and microfilm from microfilm in different formats or reductions. In particular, a reel of microfilm having frames of sequentially recorded photographic images thereon is loaded into a microfilm film transport and the microfilm is automatically stepped, frame by frame, past a film-illuminating device. The frames on the microfilm are reduced in size by a reducing lens and imaged at a plane within a microfilm recorder device. The microfilm recorder device is automatically controlled in a manner whereby film contained therein is movable in two dimensions in a plane which is coplanar with the image focal plane. The movement of the film is such that a plurality of frames or microimages arranged in columns and rows and corresponding to the microfilm frames being illuminated are arranged on the film in a preselected microfiche format.

Abstract: Method and apparatus for use in a web transport system wherein the web is stopped at a position it occupied when an event occurs. In particular, a motor driven capstan is provided to drive a web, such as a filmstrip, between first and second reels. A tachometer, operatively coupled to the capstan motor, provides a first signal representing the actual film velocity. The first signal is applied to an integrator which is controlled in a manner whereby during normal operation of the web transport system the integrator is off and does not affect system performance. When the event occurs requesting the capstan drive motor to stop, the integrator is enabled and provides an output which is proportional to the distance traveled during deceleration of the capstan drive motor (overshoot). The output of the integrator is coupled to first summing junction whereat it is added to a signal representing the desired film velocity which is driven to zero upon occurrence of the event.

Abstract: An improved system for the determination of pitch or perceived frequency of signals generated by musical instruments or voices and for the display of the results in a format easily understood and used by musicians. An incoming signal from a microphone is peak detected after amplification, then further processed by rejecting spurious peaks through the use of an inhibit circuit which sends onward acceptable pulses and inhibits those pulses which arrive during a period immediately following each accepted pulse, the period being approximately 3/8 of the time between acceptable pulses. These pulses drive a period measuring circuit which provides a signal proportional to the time between input pulses, the signal being fed back to the inhibit circuit for its proper operation and being fed forward to the readout display where the results are translated into convenient musical notation, like C.sub.+.sub.1 .music-sharp..