Abstract: Discussed herein is a method of positioning a printer's drive roller relative to the printer's printhead. The printhead has rows of individual print elements arranged to apply transverse dot rows to a print medium. To print at a desired location on the print medium, the printer initiates a first drive roller advance to the desired location, at a relatively fast slew speed. Assuming some overshoot or undershoot occurs, the printer then determines the actual position error of the drive roller, and selects a set of the printhead rows that correspond most closely in position to the desired print location. The printer then initiates a second drive roller advance, at a relatively slow speed, to position the selected group of printhead rows accurately over the desired print location on the print medium. These printhead rows are then used to perform the actual printing. The slow speed of the second drive roller advance ensures high positioning accuracy.

Abstract: Discussed herein is a method of positioning a printer's drive roller relative to the printer's printhead. The printhead has rows of individual print elements arranged to apply transverse dot rows to a print medium. To print at a desired location on the print medium, the printer initiates a first drive roller advance to the desired location, at a relatively fast slew speed. Assuming some overshoot or undershoot occurs, the printer then determines the actual position error of the drive roller, and selects a set of the printhead rows that correspond most closely in position to the desired print location. The printer then initiates a second drive roller advance, at a relatively slow speed, to position the selected group of printhead rows accurately over the desired print location on the print medium. These printhead rows are then used to perform the actual printing. The slow speed of the second drive roller advance ensures high positioning accuracy.

Abstract: Optical encoder system designs and methods for use thereof in printing devices are disclosed which are directed to solving problems caused by contaminant matter accumulating on optical encoder strips as well as scratching of optical encoder strips. An embodiment includes a dispenser and a take-up mechanism. The dispenser includes an encoder strip having first and second lengths. The second length of encoder strip is substantially free of contaminant matter. The first length of the encoder strip is coupled to the take-up mechanism so that the first length of the encoder strip is positioned between the dispenser and take-up mechanism. The take-up mechanism is configured to advance at least a portion of the second length of the encoder strip from the dispenser to a position between the dispenser and take-up mechanism upon actuation of the take-up mechanism.

Abstract: An isolated amplifier, typically a biomedical amplifier, includes a main amplifier having inputs for receiving signals, a circuit for sensing a common mode voltage received by the inputs from the electrodes and providing a compensation voltage representative of the common mode voltage, and a capacitance to chassis ground for receiving a voltage representative of the compensation voltage. The circuit and the capacitance cause the amplifier power supply voltages to track the common mode voltage. The capacitance permits the feedback loop gain to be increased, thereby reducing common mode voltage errors.

Abstract: An aircraft security system includes a central control unit, several remotely located cluster controllers and a plurality of intrusion sensors associated with and controlled by each cluster controller. A two-wire bus carries power from the central control unit for operating each of the cluster controllers and the sensors, and carries data signals in both directions between the central control unit and the cluster controllers. The two-wire bus reduces weight and installation costs. The system includes an initial calibration mode wherein sensor type information and sensor parameters are sent from the central control unit to each cluster controller. The signal strength from each sensor is then measured and stored in the central control unit. During later operation, the sensor signal strengths are measured and compared with the initial values. If a trouble condition is detected, appropriate corrective action is taken.

Abstract: An aircraft security system includes a central control unit, several remotely located cluster controllers and a plurality of intrusion sensors associated with and controlled by each cluster controller. A two-wire bus carries power from the central control unit for operating each of the cluster controllers and the sensors, and carries data signals in both directions between the central control unit and the cluster controllers. The two-wire bus reduces weight and installation costs. The system includes an initial calibration mode wherein sensor type information and sensor parameters are sent from the central control unit to each cluster controller. The signal strength from each sensor is then measured and stored in the central control unit. During later operation, the sensor signal strengths are measured and compared with the initial values. If a trouble condition is detected, appropriate corrective action is taken.

Abstract: An error-detection circuit (10) employs comparison circuitry (12) to determine whether a SENSE signal is within a range indicated by XPRANGE signals. When the SENSE signal goes into or out of the indicated range, an INRANGE output of the comparison circuitry (12) moves through a predetermined voltage swing from one stable level through a threshold level to another stable level. The passage of the INRANGE signal through the threshold level is an indication to subsequent circuitry that SENSE has passed into or out of the indicated range. According to the present invention, one or other of the levels occupied by the INRANGE signal is separated from the threshold by a voltage that is only a small fraction of the swing between the two levels. As a consequence, the delay between the transition of the SENSE signal and the transition of the INRANGE output of the comparison circuitry is only a small fraction of the time required to complete the voltage swing.