Abstract: A step-up circuit involves a short step-up time and improved step-up efficiency. The step-up circuit has capacitors. First and second power source voltages are applied to the first and second electrodes of each capacitor, respectively. Thereafter, the capacitors are connected in series so that the second electrode of the first capacitor is connected to the first electrode of the second capacitor. At this time, the second power source voltage is applied to the first electrode of the first capacitor, and the potential of the second electrode of each capacitor is provided as an output voltage.

Abstract: In the PC-based teleconference terminal 200 includes a PC 110 and a video codec unit 130, a network control unit 220 and an audio codec unit 240 which are all constructed on the same expansion board, with the video codec unit 130, the audio codec unit 240 and the network control unit 240 all connected to the computer bus 114 so as to be able to transfer audio data, video data, data and AV multiframes between themselves. The audio codec unit 240 is equipped with a audio clock generation unit 241 for generating an audio sampling signal of 8 kHz through self-excited oscillation.

Abstract: A method for controlling opening/closing of a door in an automatic door system comprises the steps of causing the door to conduct opening operation to its opening-stop limit by an initial opening signal transmitted after the power supply is put to work and the arrival of the door at its closing-stop point is confirmed, and measuring the opening stroke at that time; causing the door to conduct closing operation to its closing-stop point when it is stopped at opening-stop point and no opening signal is inputted, and measuring the closing stroke of the door at that time; computing the difference between the measured opening and closing strokes upon stopping of the door at its closing-stop point; and outputting a signal of abnormal condition if the difference is more than a present value, or causing the door to conduct normal opening/closing operation if it is less than the preset value.

Abstract: An apparatus for detecting door movement data in an automatic door system is improved in that an opening-direction sensor and a closing-direction sensor are provided on a horizontal member of a slide door frame, while a slide door is provided with a dog having a plurality of actuating portions adapted to switch ON or OFF the opening-direction sensor and the closing-direction sensor as arrayed at an interval in the direction of sliding, so that the opening direction sensor and the closing direction sensor may be switched ON and OFF repeatedly as the door is moved in the opening or closing direction.