• An Analog Memory Device

      Uzunoglu, Vasil; COMSAT Laboratories (International Foundation for Telemetering, 1975-10)
      The analog memory device is a combination of a bipolar and a MOSFET device which stores information in analog form for several hours or more with no degradation of data. The emitter base junction of a bipolar transistor is covered with an SiO₂ layer and a voltage is applied to this point. With zero volts applied, the unit acts as a bipolar transistor. Increasing the voltage at this point increases the emitter injection efficiency of the bipolar transistor, which in turn increases the current gain of the device. An SiO₂ layer with no leakage paths can retain the charge applied to it for long periods of time; thus the gain will remain at this level as long as the charge remains on the oxide layer. A large number of such devices can be fabricated on a single chip. Such devices combined with other integrated circuits can be used, for example, for automatic equalization of transmission lines, echo suppression, and correlation detection.
    • COMSAT General Ranging Equipment Development

      Onufry, Michael; Jankowski, Joseph A.; COMSAT Laboratories (International Foundation for Telemetering, 1975-10)
      The range to the spacecraft is an important parameter for determining the transfer and synchronous orbits. The ranging equipment developed for the COMSAT General TT&C earth stations uses a fixed-tone technique to determine the distance from the earth station antenna to the satellites. Specifically, the range is calculated from the round trip propagation delay, which is determined by measuring the phase shift in four coherent audio tones. This system is similar to the ranging equipment used at the INTELSAT earth stations. New integrated circuit (IC) technology has permitted individual tone transmission which was previously not available. The ranging tones are frequency modulated in both the up- and down-links in the INTELSAT system. However, in the COMSAT General system the tones are frequency modulated in the up-link and phase modulated in the down-link. Hence, new techniques are required to determine the phase shift of the earth station equipment.