Abstract: Each storage cell in an automated storage and retrieval system is provided with a mark, such as a bar code label, which is detectable to a vision system when the cell is empty. Further, each item storable in a cell is also provided with a mark, such as a bar code label uniquely identifying the item, which is detectable by the vision system. During an inventory of the contents of the system, the vision system is moved across the openings of the cells and scans for the marks. If an item mark is detected, entries in a data table are made indicating the location of the cell being scanned and its occupied status. The identity of the item detected can also be entered into the data table. On the other hand, if a cell mark is detected, entries in a data table are made indicating the location of the cell being scanned and its empty status. If neither mark is detected at a cell, additional steps can be initiated to determine the status of the cell.

Abstract: An improved driver design including a plurality of NPN bipolar driver transistors connected in an H configuration including at least one bipolar upper drive transistor. A novel circuit is included for driving the upper NPN bipolar driver transistor. In a particular implementation, the circuit for driving the upper bipolar drive transistor is adapted to sense the output of the drive transistor and regulate a voltage at the input thereof in response thereto to keep the drive transistor out of saturation. Thus, power dissipation is minimized by using an H configuration and high speed is afforded by using bipolar drive transistors and by keeping the drive transistors out of saturation.

Abstract: In a magnetic tape readback system for a multi-track tape player, a phase lock loop is provided for each of the channel circuits used for reading signals from the respective tracks on a multi-track tape. A common frequency determining capacitor is coupled to all of the phase lock loops such that the frequency of operation of the phase lock loops is stabilized. The capacitor has a capacitance usable in the individual phase lock loops for determining a frequency of operation and it is commonly AC connected to all of the phase lock loops. A capacitance AC couples and DC blocks each of the individual phase lock loops to the frequency determining capacitor such that the individual phase lock loops have their own reference DC levels and yet receive AC input from all of the other phase lock loops.

Abstract: A magnetic tape readback system is disclosed for a multi-track tape player. A single phase lock loop is provided for the channel circuits used for reading signals from the respective tracks on a multi-track tape. A common frequency determining circuit means is coupled to all of the phase lock loops such that the frequency of operation of the phase lock loops is stabilized. A capacitor which has a capacitance usable in the individual phase lock loops for determining a frequency of operation is commonly AC connected to all of the phase lock loops; in this arrangement none of the phase lock loops have the frequency determining capacitor. A capacitance AC couples and DC blocks each of the individual phase lock loops to the frequency determining capacitor such that the individual phase lock loops have their own reference DC levels and yet receive AC input from all of the other phase lock loops.