Abstract: A dual regulated DC power supply produces an output voltage which is the sum of a variable DC control voltage and a floating DC voltage. The control voltage, generated by a first differential amplifier having an inverted input coupled to the power supply output through a feedback scaling circuit, varies in inverse relation to the change in power supply output voltage. The floating DC voltage is produced by isolating, rectifying and filtering the output of an oscillator having a peak voltage controlled by an applied bias voltage. The applied bias voltage is generated by a second differential amplifier coupled to compare the control voltage with a selected reference voltage so that a change in control voltage causes a change in the floating voltage. The control voltage changes rapidly in compensating response to transient changes in power supply voltage while the floating voltage changes more slowly in compensating response to output voltage changes due to sustained load swings.

Abstract: A compensation circuit is described for use in a line scan type recording apparatus where an electron beam is scanned on the face of a fiber optic cathode-ray tube (FOCRT) in synchronization with a movable recharging medium. The compensation circuit includes a charge pump circuit, an integrator circuit, and a current source. The charge pump circuit draws a constant charge from the integrator circuit in response to a repetitive series of stepper pulse corresponding to the velocity changes in the recording medium. The current source generates a constant current that flows into the integrator circuit and is equal to the average DC current flowing out of the integrator circuit via the charge pump circuit. The output voltage of the integrator circuit is used for controlling the vertical displacement of the electron beam of the FOCRT in synchronization with the movable recording medium.

Abstract: Provided are an apparatus and a method for recording on a recording medium images from a fiber-optic CRT. The apparatus includes a recording medium transport system, control electronics and a first-in, first-out memory. The use of the first-in, first-out memory permits incremental recording which is not limited by relatively long mechanical transport settling times. In operation, N lines of data are input to the memory, line-by-line, as the transport system increments the position of the recording medium and during settling time. When the recording medium has come to rest, these N lines of data are output sequentially from the memory in a first-in, first-out basis, with the CRT incrementing each line vertically on the recording medium for the total of N lines for each increment of the recording medium by the transport system.

Abstract: In a line scan graphic recording apparatus, the beam which displays the data on the recording media must be synchronized with the movement of recording media as it is directed normal to the displaying apparatus. The rate at which the recording media moves in its path is determined by the paper drive means. The rate is often non-uniform due to instantanteous velocity variations of the drive means. A drive velocity sensor produces a timing signal which controls the recording time of the input data image, stored digitally in a buffer memory device, by triggering the buffering device at the appropriate time and causing the image data to be transferred to the display for recording on the selected media.

Abstract: The present invention relates to a drive circuit for a stepping motor. The drive circuit provides a low voltage to the coils of the stepping motor in the steady state, and a high voltage to the coils when changing state. As a result, the state changes rapidly and the stepping motor is driven efficiently. The high voltage is derived from the energy which was stored in the winding of the stepping motor before the switching occurred by transferring that energy to a capacitor which achieves a charge potential that is greater than the potential of the power supply voltage.

Abstract: A circuit is described for automatically controlling an input current to a current translating device having an output current functionally related to the input current. A sensing circuit detects the output current of the device and produces a control signal representative of the output current. The control signal is coupled to a control circuit that varies the input current to the device. In the preferred embodiment of the invention, the dynamic range of the sensing circuit is increased by coupling a constant current generator to its input.

Abstract: A circuit, including a dual-mode amplifier, for producing a controlled current through an inductance; in particular, the inductive yoke of a cathode-ray tube electromagnetic deflection system. A diode coupled to a fly-back capacitor operates automatically to connect the capacitor in parallel resonant connection with the yoke whenever the voltage induced in the yoke exceeds a predetermined value, thereby switching the circuit from a linear mode to a non-linear mode. In a repetitive beam-sweeping environment, the circuit operates in the linear mode during forward scan time and in the non-linear mode during reverse retrace time. In the more general case, the circuit switches from linear operation to non-linear operation whenever the rate of change of a single input signal exceeds a predetermined design rate.