Patents by Inventor Eric K. Pritchard

Eric K. Pritchard has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5157484
    Abstract: A single camera autostereoscopic recording system includes a single image recorder having a single optical path moved along the scanning path substantially continuously for a plurality of scanning cycles. A path defining structure includes the ability to adjust the convergent point as well as the extent of travel along the scanning path or disparity of the images. The convergent point of the scanning path can be manually or automatically adjusted using a range finder. A unique driver structure provides scanning motion with reduced reactional forces. The degree of motion of the recorded images is used to adjust the amount of travel along the scanning path. Synchronization between the driver and the recorder is bi-directional for double exposures. The recorded image is adjusted in recording or in display as a function of the position in the scanning path.
    Type: Grant
    Filed: November 29, 1990
    Date of Patent: October 20, 1992
    Assignee: Vision III Imaging, Inc.
    Inventors: Eric K. Pritchard, Christopher A. Mayhew
  • Patent number: 5133014
    Abstract: A distortion synthesizer, having a first distortion circuit, a tone control circuit for altering the tonality of the first distorted signal and a second distortion circuit for introducing harmonics into said tone controlled signal. At least one of the distortion circuits introduces harmonics without clipping. The second distortion circuit also for clips the resultant signal as a function of said resultant signal. The first distortion circuit limits and introduces even harmonics, preferrably predominantly second harmonics. The second distortion circuit introduces odd harmonics, preferrably by predominantly third harmonics, prior to clipping, and also compress the signal. The distortion circuits include a variable gain stage which increases with increased input using a plurality of switches which progressively add parallel resistors to progressively increase output current. A circuit simulating transformer saturation is also provided in the second distortion circuit.
    Type: Grant
    Filed: January 18, 1990
    Date of Patent: July 21, 1992
    Inventor: Eric K. Pritchard
  • Patent number: 5113253
    Abstract: A single camera autostereoscopic recording system includes a single image recorder having a single optical path moved along the scanning path substantially continuously for a plurality of scanning cycles. A path defining structure includes the ability to adjust the convergent point as well as the extent of travel along the scanning path or disparity of the images. The convergent point of the scanning path can be manually or automatically adjusted using a range finder. A unique driver structure provides scanning motion with reduced reactional forces. The degree of motion of the recorded images is used to adjust the amount of travel along the scanning path. Synchronization between the driver and the recorder is bi-directional for double exposures. The recorded image is adjusted in recording or in display as a function of the position in the scanning path.
    Type: Grant
    Filed: November 29, 1990
    Date of Patent: May 12, 1992
    Assignee: Vision III Imaging, Inc.
    Inventors: Eric K. Pritchard, Christopher A. Mayhew
  • Patent number: 5014126
    Abstract: The method and apparatus substantially continuously changes the view of a single image receive substantially aligned to a convergent point in a scene, along a scanning path and recording a plurality of scanning images for each cycle of traversing the scanning path. The scanning path and the scanning and recording rates are selected to produce motion within visio-psychological memory rate range when displayed using standard display devices.
    Type: Grant
    Filed: October 23, 1989
    Date of Patent: May 7, 1991
    Assignee: Vision III Imaging, Inc.
    Inventors: Eric K. Pritchard, Christopher A. Mayhew
  • Patent number: 4995084
    Abstract: A semiconductor system analog or digital processor (402) for emulating a vacuum tube amplifier having first distortion (372), tone control (373), and second distortion (374) circuits. The first distortion circuit (372) variably introduces even harmonics and the second distortion circuit (374) introduces even and odd harmonics. The second distortion circuit includes a variable gain circuit using diodes (275-286) and resistors (287-293) to progressively increase output current with increasing input voltage and clipping circuit. A speaker driving a microphone emulation circuit (379) is also provided. A distortion circuit varies the gain and harmonic contents as a function of amplitude, duration and number of cycles. An asymmetrical bias shifting circuit (60, 70) with a limiter also introduces even harmonics.
    Type: Grant
    Filed: November 1, 1988
    Date of Patent: February 19, 1991
    Inventor: Eric K. Pritchard
  • Patent number: 4966436
    Abstract: A method is provided for obtaining images for use in displaying a three-dimensional illusion which includes the step of obtaining first and second images of a subject volume having foreground and background portions with the points of origin of those images located in a first plane which includes left and right points of origin of an observer of the subject volume and which is normal to the optical axis of that observer. The first and second points of origin are also respectively located equidistant above and below a first line interconnecting the left and right points of origin and are located along a second line which is normal to and bisects the first line. The first and second optical axes are aligned to converge in a second plane parallel to the first plane which includes the foreground portion of the subject volume within the field of view of the observer which is closest to the first plane.
    Type: Grant
    Filed: February 13, 1989
    Date of Patent: October 30, 1990
    Assignee: Christopher A. Mayhew
    Inventors: Christopher A. Mayhew, Eric K. Pritchard
  • Patent number: 4815819
    Abstract: A method is provided for obtaining images for use in displaying a three-dimensional illusion which includes the step of obtaining first and second images of a subject volume having foreground and background portions with the points of origin of those images located in a first plane which includes left and right points of origin of an observer of the subject volume and which is normal to the optical axis of that observer. The first and second points of origin are also respectively located equidistant above and below a first line interconnecting the left and right points of origin and are located along a second line which is normal to and bisects the first line. The first and second optical axes are aligned to converge in a second plane parallel to the first plane which includes the foreground portion of the subject volume within the field of view of the observer which is closest to the first plane.
    Type: Grant
    Filed: April 30, 1987
    Date of Patent: March 28, 1989
    Assignee: Christopher A. Mayhew
    Inventors: Christopher A. Mayhew, Eric K. Pritchard
  • Patent number: 4809336
    Abstract: A distortion synthesizer having a transformerless filter of a defined bandwidth and providing circuitry for narrowing of the bandwidth filter as a function of the amplitude of the input signal. This includes an input amplifier having a limiter connected between the input amplifier and the band pass filter with feedback between the output of the band pass filter and the input of the amplifier. The limiter is actuated at a given input signal to limit the amplitude and thereby reduce the feedback narrowing the frequency response. A bias shifter connected to the input of the amplifier asymmetrically transmits the input signal and in combination with the limiter produces even harmonics. A feed forward embodiment is also disclosed. Diode structure provided in an output stage brings flyback into the audible range allowing the flyback voltages to exceed the power supply voltages. The time constant of the bias shifter is sufficiently long to prolong the bias shifting to allow attack time for the note.
    Type: Grant
    Filed: March 23, 1987
    Date of Patent: February 28, 1989
    Inventor: Eric K. Pritchard
  • Patent number: 4589321
    Abstract: A string attachment device having a sleeve encompassing a cam, an aperture in the sleeve to position a string therebetween and means to rotate the sleeve and cam relative to each other to grasp the string therebetween.
    Type: Grant
    Filed: June 25, 1984
    Date of Patent: May 20, 1986
    Assignee: Paul Reed Smith
    Inventor: Eric K. Pritchard
  • Patent number: 4584512
    Abstract: These microstepping stepping motor drives have analog and digital embodiments which generate tunable motor current waveforms to reduce low-frequency resonance effects and to make the microsteps more accurate. One digital driver is based upon a microprocessor which includes means for altering the motor current waveforms during a setup mode in response to sensed motor motion. The basis for this operation is in antecedant applications. The waveform alteration process iterates on the harmonic content of the motor motion to alter waveform determining values. The controller also has the capability of creating default motor current waveforms from an input code. It also has the control capability of pulse buffers, and can follow an external velocity input.
    Type: Grant
    Filed: December 7, 1983
    Date of Patent: April 22, 1986
    Inventor: Eric K. Pritchard
  • Patent number: 4449196
    Abstract: A numerically controlled machine includes a first computer which stores command data for a path and derives sets of interpolation point data from said command data for a plurality of points along the path. A second computer stores two sets of interpolation point data from said first computer and extrapolates a set of said stored interpolation point data by incrementing velocity with acceleration and position with velocity using a noncircular high order polynomial to produce a sequence of driver command signals.A timing means provides timing signals to the second computer to determine the number and rate of iterations of drive command signals in said sequence as predetermined by the first computer for each set of interpolation point data.The program execution time in the second computer is reduced by a unique method of multiprecision calculation which requires a carry flip flop for each variable calculated and a sign flip flop for eliminated word segments.
    Type: Grant
    Filed: October 2, 1980
    Date of Patent: May 15, 1984
    Inventor: Eric K. Pritchard
  • Patent number: 4350943
    Abstract: This switching amplifier is for driving inductive loads, stepping motors in particular. This amplifier uses dual threshold concept with improvements to the current feedback. These improvements compensate for errors in the feedback signals of the prior art. These improvements measure currents erroneously omitted or included in the feedback signal and add or subtract said measurements from said feedback to improve signal fidelity.
    Type: Grant
    Filed: April 4, 1980
    Date of Patent: September 21, 1982
    Inventor: Eric K. Pritchard
  • Patent number: 4339701
    Abstract: The switching amplifiers of the prior art improved by a variable hysteresis in the comparator circuitry of said amplifier. Said variable hysteresis is controlled by the power supply voltage and a frequency sensitive feedback circuit. If the amplifier load creates an excessive frequency which cannot be controlled, a fault detector circuit disables the amplifier.
    Type: Grant
    Filed: April 11, 1980
    Date of Patent: July 13, 1982
    Inventor: Eric K. Pritchard
  • Patent number: 4302712
    Abstract: A stepping motor driver is adjusted to minimize resonance by adjusting a variable frequency source to adjust the fundamental frequency of the drive to the frequency of a filter, driving the driver and motor with the adjusted frequency source, sensing the motion of the motor and providing the sensed motion to an indicator through the filter. The driver is adjusted to minimize the indication. Adjustment at various harmonics are performed by using 1/N the adjusted frequency, where N is the harmonic of interest.The improved driver includes a plurality of voltage sources adjustable for resonance compensation at the fundamental frequency and 1/N thereof. DC offset, relative gain and orthogonality of the motor driver signal adjustments are provided.
    Type: Grant
    Filed: February 27, 1980
    Date of Patent: November 24, 1981
    Inventor: Eric K. Pritchard
  • Patent number: 4272713
    Abstract: A switching current amplifier for stepping motors utilizing a square hysteresis loop transformer to measure the motor winding load current directly, to determine the high and low switching points in reference to the position command signal, to compare the motor winding current to the determined switching points and to provide a switching signal to switch the output devices of the amplifier when the motor winding current reaches the switching points. The square hysteresis loop transformer is constructed to have a high common mode signal rejection.
    Type: Grant
    Filed: October 30, 1979
    Date of Patent: June 9, 1981
    Inventor: Eric K. Pritchard
  • Patent number: 4262336
    Abstract: In a numerically controlled machine includes a first computer which stores command data for a path and derives sets of interpolation point data from said command data for a plurality of points along the path. A second computer stores two sets of interpolation point data from said first computer and extrapolates a set of said stored interpolation point data by incrementing velocity with acceleration and position with velocity using a noncircular high order polynomial to produce a sequence of driver command signals.A timing means provides timing signals to the second computer to determine the number and rate of iterations of drive command signals in said sequence as predetermined by the first computer for each set of interpolation point data.The program execution time in the second computer is reduced by a unique method of multiprecision calculation which requires a carry flip flop for each variable calculated and a sign flip flop for eliminated word segments.
    Type: Grant
    Filed: April 27, 1979
    Date of Patent: April 14, 1981
    Inventor: Eric K. Pritchard
  • Patent number: 4214823
    Abstract: A control system for an animation stand including a stored program computer for monitoring and storing a plurality of manually produced positions of a camera and a support relative to each other and for calculating a plurality of driver command signals from said stored positions and stored time frame or control data to produce a sequence of motions of said camera and said support relative to each other. A manually induced velocity vector is used by the computer to calculate driver command signals to effectuate the manually produced positions. Each axis of motion per time frame may be individually manually produced.
    Type: Grant
    Filed: May 22, 1979
    Date of Patent: July 29, 1980
    Inventor: Eric K. Pritchard
  • Patent number: 4140956
    Abstract: A control circuit for a stepping motor is provided which rotates the motor armature in such a manner as to minimize motor resonance while not appreciably reducing the motor torque at high speeds. The circuit includes means for receiving an input signal indicative of the desired direction and rate of motor travel and means response to the input signal for developing a position command signal which is a multi-step function having a maximum and a minimum level and wherein all steps are of equal amplitude but wherein at least one step between said maximum and minimum levels has a duration which is unequal to that of another step. Finally, the circuit includes means responsive to the position command signal for developing an energization signal for the stepping motor.
    Type: Grant
    Filed: February 10, 1978
    Date of Patent: February 20, 1979
    Inventor: Eric K. Pritchard
  • Patent number: 4100471
    Abstract: A control circuit for a stepping motor is provided which rotates the motor armature in such a manner as to minimize motor resonances while not appreciably reducing the motor torque at high speeds. The motor inherently possesses a non-linear transfer function of current to flux and the circuit includes means responsive to an input signal for developing a position command signal which is a sinusoidal waveform modified by the inverse of the motor transfer function. Further means are provided responsive to the position command signal for developing an energization signal for the stepping motor including means responsive to the position command signal and motor field current for terminating a motor energization cycle.
    Type: Grant
    Filed: July 20, 1976
    Date of Patent: July 11, 1978
    Inventor: Eric K. Pritchard
  • Patent number: 4087732
    Abstract: A control circuit for a stepping motor is provided which rotates the motor armature in such a manner as to minimize motor resonance while not appreciably reducing the motor torque at high speeds. The circuit includes means for receiving an input signal indicative of the desired direction and rate of motor travel and means responsive to the input signal for developing a position command signal which is a multi-step function having a maximum and a minimum level and wherein all steps are of equal amplitude but wherein at least one step between said maximum and minimum levels has a duration which is unequal to that of another step. Finally, the circuit includes means responsive to the position command signal for developing an energization signal for the stepping motor.
    Type: Grant
    Filed: May 21, 1976
    Date of Patent: May 2, 1978
    Inventor: Eric K. Pritchard