Mcc Associates

Other

Amtech Patent Licensing Corp.

Mss Associates

David Chiang

Mosi Chu

Solomon Manber

A FIR (finite impulse response) type digital filter operates on digital audio signals in modern sound reproduction systems. It is shown that this operation forces the loudspeaker to produce a sound pressure wave having the original signal waveform. Given a multi-driver speaker, its response to a known broad band analog signal (impulsive) is sampled at least as fast as the Nyquist rate. The result is used to construct a deconvolution filter which compacts, in the least-squares sense, the blurred signal (speaker output) back into its original waveform. Since this anti-blurring process is linear and time invariant, it can be applied to the speaker driving signal as a blur preventive. A fine-tuning procedure utilizing Lagrange's Method of Multipliers modifies the deconvolution process such that the blur-free speaker output achieves a degree of flatness in frequency response beyond what could be attained with a simple deconvolution filter.

Tuned deconvolution digital filter for elimination of loudspeaker output

A paper tray having a bottom, front and rear walls extending upwardly from the bottom, and side walls extending upwardly from the bottom to define an open boxlike structure for storage of sheets of paper in readiness for use. A paper receiver is pivotably mounted on the tray for receiving sheets of paper after printing thereof. The paper receiver has a first position in which paper can be fed automatically from the tray to a print roller and a second position in which paper can be manually fed to the print roller. In the automatic mode, the paper is fed by a drive roller to produce a buckle at its leading position to insure alignment at the print roller and subsequent straight, unskewed feed. The paper receiver carries a conveyor belt driven from the print roller at a greater linear speed to insure positive feed of the paper from the print roller to a receiving station.

Paper supply and stacking apparatus

A method of stopping a feedback-controlled stepping motor having a stator and a rotor wherein the drive of the stator field is leading the rotor by more than one step and the rotor is rotating with an angular velocity within a first range of values is performed by decreasing the drive lead of the stator field from its slewing value to another value whereby the angular velocity of the rotor decreases below the first range and sensing for the decrease of the angular velocity of the rotor to within a second range of values so that when the angular velocity of the rotor is within the second range of values the rotation of the stator field is stopped to brake the rotor.

Method of stopping a stepping motor

A paper tray has a first bottom, first front and rear walls extending upwardly from the first bottom, first and second side walls extending upwardly from this bottom. The walls and bottom define an open boxlike structure for storage of sheets of paper prior to use. A cover is pivotably mounted to the top of the lower side walls in the region of the rear wall extends toward the first front wall. The cover is shorter than the first bottom to provide a feed gap between the free end of the cover and the front wall so that paper can be removed from the boxlike structure. Each of the lower side walls has an extension upwardly extending beyond the level of the cover. Paper receiving means has a second bottom upwardly displaced from and overhanging the feed gap and the front wall. First and second upper side walls are connected to the ends of the extensions remote from the rear wall and extend upwardly from the upper bottom. A front wall extending upwardly from the edge of the second bottom remote from the connection to the extensions. The second bottom, the upper side walls and front wall define a receptacle for receiving after use sheets of paper initially stored in the defined open boxlike structure.

For a stepping motor having a rotatable stator magnetic field for driving the rotor, there is disclosed a method of damping the oscillations of the rotor which occurs when the rotatable stator magnetic field is stopped upon arriving at a desired rotational position by measuring quantities related to the instantaneous velocity of the rotor due to the oscillations of the rotor about the desired rotational position, rotationally displacing the stator magnetic field from the desired rotational position in a direction opposite to the direction of the oscillation, and thereafter returning the stator magnetic field to the desired stopping position.

Method of damping a stepping motor

Apparatus for recording characters on a photographic record medium including spaced feed and takeup reels for carrying a roll of the medium. A support such as a cylinder is disposed between the reels supports the record medium. A carriage is controllably movable opposite the support and in a direction transverse to the direction of record medium movement. A recording head on the carriage has a radiation emitter device for emitting intensity modulated radiation toward the cylindrical support along a scan line which makes an angle with the direction of the transverse movement.

Indicia recording apparatus

A clock generator for establishing working clock pulses occurring for constant increments in a scan path of a laser scanner which cyclically sweeps over a record medium at a non-constant velocity includes: a generator of a fiducial pulse at least once per cycle of sweep; a frequency synthesizer responsive to the fiducial pulses for generating radio-frequency clock pulses having a frequency greater than the fiducial pulses, and in synchronization therewith; a storage for storing a plurality of count values, each of the count values being associated with a given increment along the scan path; a working clock pulse generator, including a counter which counts the radio-frequency clock pulses, for emitting a working clock pulse each time the counter counts a count value received by the working clock pulse generator. For each working clock pulse a new count value stored in the storage is transmitted to the working clock pulse generator.

Clock generator

A stepping motor system is shown wherein a method is employed for determining the optimum amplitude of the current supplied to the stator winding of the motor. A series of different currents are applied to the motor. First, the stator windings are energized with currents of certain base magnitudes. Then the current in one winding is increased by a small amount and the current in the adjacent winding is decreased by a small amount so that the rotor tends to move towards its new equilibrium position. When the rotor reaches its maximum displacement the current changes in the windings are reversed so that not only will the rotor 'hunt' for its new equilibrium position but it overshoots with twice the magnitude. This process continues for certain period of time during which the oscillation magnitudes rapidly grow. In one embodiment, after a maximum amplitude is reached, the current changes are applied out of phase with the oscillations to now try to decrease their amplitude. After another period of time, the current changes are terminated, the residual oscillations are monitored and all oscillations greater than a given amplitude are recorded. As this process can be repeated for different base currents, that current which yields the minimum number of 'over' oscillations during the monitoring period is selected as the current amplitude for subsequent use in positioning the rotor. In another embodiment, the damping portions of the method is not performed. Then, the base current is selected which results in the greatest number of 'over' oscillations. According to another aspect of the invention, the oscillation is used to determine the torque for a given current.

Method of determining operating parameters for a stepping motor

Apparatus for recording characters on a photographic record medium including spaced feed and takeup reels for carrying a roll of the medium. A cylindrical support disposed between the reels supports the record medium. A carriage is controllably movable opposite the cylindrical support and in a direction along the cylindrical axis of the latter. A recording head on the carriage has a radiation emitter device for emitting intensity modulated radiation toward the cylindrical support along a scan line which is in a plane intersecting such cylindrical axis.

A stepping motor system is shown wherein a method is employed for determining the optimum amplitude of the current supplied to the stator winding of the motor. A series of different currents are applied to the motor. First, the stator windings are energized with currents of certain base magnitudes. Then the current in one winding is increased by a small amount and the current in the adjacent winding is decreased by a small amount so that the rotor tends to move towards its new equilibrium position. When the rotor reaches its maximum displacement the current changes in the windings are reversed so that not only will the rotor 'hunt' for its new equilibrium position but it overshoots with twice the magnitude. This process continues for a certain period of time during which the oscillation magnitudes rapidly grow. In one embodiment, after a maximum amplitude is reached, the current changes are applied out of phase with the oscillations to now try to decrease their amplitude. After another period of time, the current changes are terminated, the residual oscillations are monitored and all oscillations greater than a given amplitude are recorded. As this process can be repeated for different base currents, that current which yields the minimum number of 'over' oscillations during the monitoring period is selected as the current amplitude for subsequent use in positioning the rotor. In another embodiment, the damping portions of the method is not performed. Then, the base current is selected which results in the greatest number of 'over' oscillations.

Method of determining operating currents for stepping motor

A method and apparatus for driving a stepping motor by angularly displacing the revolvable magnetic field with respect to the rotor by a first displacement angle in a given direction of revolution and then revolving the revolvable magnetic field, preferably with linearly increasing velocity and therefore maintaining constant displacement angle between the field and the rotor until the rotor rotates at a second velocity.

Method of and apparatus for operating stepping motors

An open loop control device and method are provided for stepping motors. By energizing a motor so that the rotor motion is the result of a revolving field which is of piecewise constant speed and uniform field strength, the rotor can be brought to a stop at any desired position. Such position can be the same as or different from the conventional full-increment or half-increment detent positions of the motor. This control method and device guarantee that there is no oscillation when the rotor reaches its final position. The field windings are energized in sequential manner and such that the resultant field takes into account the magnetic characteristics of the motor. The revolving field can be initially adapted to produce, in one case, an angular velocity of half the desired speed for purposes of accelerating the rotor. After one-half of a resonant period has elapsed, the rotor is accelerated to the desired speed. At this time, the speed of the field is doubled and the rotor fully synchronized therewith. When the rotor is to be stopped, the field velocity is switched to an angular velocity equivalent to that of the acceleration velocity which is half the constant speed velocity and the rotor therefore overshoots. Half of a resonant time period later, the rotating field is stopped and the rotor comes to a standstill without oscillation since the field is precisely aligned with the rotor at the instant of stopping. Also, a method is provided for establishing current forms or patterns for the windings of a multi-phase stepping motor to provide the uniform revolving field taking into account the magnetic characteristics of the motor. This method comprises, for each of the pairs of windings which are sequentially effective to drive the rotor of the stepping motor, the steps of driving one winding of the pair with maximum running current and measuring rotor stiffness at the resultant detent position, and thereafter passing a relatively small current through the other winding of the pair and reducing the current through the first winding to displace the rotor to a position which is a fraction of a distance towards the next detent position. These two currents are adjusted to obtain a rotor stiffness equal to the first rotor stiffness while maintaining rotor position. Subsequent steps involve sequentially displacing the rotor and repeating the process to obtain a current curve which will generate the aforesaid revolving field with constant velocity and uniform strength despite magnetic characteristics of the components of the stepping motor involved.

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Dix Hills, NY, United States of America

David Chiang