Abstract: The determination of deterioration of a NOx storage reduction catalyst (4) is carried out more accurately. When a reducing agent is supplied from a supply device (5) to the NOx catalyst (4), a first supply of the reducing agent and a second supply of the reducing agent are carried out in a sequential manner by adjusting an amount of the reducing agent in such a manner that an air fuel ratio of the exhaust gas becomes a predetermined rich air fuel ratio, and a determination whether or not the NOx catalyst (4) has deteriorated is made based on a detected value of a detection device (8), which detects NH3 in the exhaust gas at the downstream side of the NOx catalyst (4), after a predetermined period of time has elapsed from the start of the first supply of the reducing agent, and after the start of the second supply of the reducing agent.

Abstract: The deterioration judgment for an absorption reduction type NOx catalyst is performed quickly and correctly. A catalyst deterioration judging system includes a judging unit which judges that the absorption reduction type NOx catalyst is deteriorated if a detected value of an NH3 detecting unit is not more than a threshold value within a predetermined time immediately after starting supply of a reducing agent from a supply unit while regulating an amount of the reducing agent so that the air-fuel ratio of an exhaust gas is a rich air-fuel ratio by means of a control unit when NOx is absorbed by the absorption reduction type NOx catalyst.

Abstract: Radio communication systems, e.g. cellular telephones, have employed a space diversity antenna system which includes a plurality of antennas. In the space diversity antenna system for use in the cellular telephone, since two antennas are positioned adjoining each other, the space diversity effect cannot be adequately provided. To solve this problem, the polarization diversity antenna system according to this invention incorporates a first antenna, a second antenna, and a conductive board on which the second antenna is fixed at a given position, thus preventing the current flowing in the conductive board from causing the reception characteristic of the second antenna to deteriorate.

Abstract: Radio communication systems, e.g. cellular telephones, have employed a space diversity antenna system which includes a plurality of antennas. In the space diversity antenna system for use in the cellular telephone, since two antennas are positioned adjoining each other, the space diversity effect cannot be adequately provided. To solve this problem, the polarization diversity antenna system according to this invention incorporates a first antenna, a second antenna, and a conductive board on which the second antenna is fixed at a given position, thus preventing the current flowing in the conductive board from causing the reception characteristic of the second antenna to deteriorate.

Abstract: Radio communication systems, e.g. cellular telephones, have employed a space diversity antenna system which includes a plurality of antennas. In the space diversity antenna system for use in the cellular telephone, since two antennas are positioned adjoining each other, the space diversity effect cannot be adequately provided. To solve this problem, the polarization diversity antenna system according to this invention incorporates a first antenna, a second antenna, and a conductive board on which the second antenna is fixed at a given position, thus preventing the current flowing in the conductive board from causing the reception characteristic of the second antenna to deteriorate.

Abstract: This invention provides a cell switching apparatus having buffer memories in which accesses of a plurality off cells can be implemented in one-cell time. The cell switching apparatus arranges a plurality of buffer memories, in which accesses of a plurality of cells can be performed, in parallel, and schedules a score table so that the writing and reading out operations may not overlap. Accordingly, the incoming lines may be increased lip to (the number of incoming lines n)=(the number of buffer memories p-1).times.(the number of outgoing lines m) without increasing the access speed of the buffer memories.

Abstract: A data queuing apparatus processes data switching and queuing using a smaller capacity memory, while reducing data discard and loss possibility. Received limited-length data at the input line is written in shift memories, which can shift the data to the next stage regardless of the destination of the data. Destination indicating bits, which indicate the destination of the data, are associated with each of shift memories. A search circuit detects an asserted bit among the destination indicating bits corresponding to the output lines. The data is extracted by a selector. Then the selector transmits the data to the desired output line, and the data stored in the previous stage of the shift memory is shifted. The memory is used in common with a plurality of output lines, so that a lower possibility of data discard and loss can be attained in a smaller capacity memory.

Abstract: An ATM cell exchanging apparatus includes an ATM cell switch for a first system #1 and an ATM cell switch for a second system. These cell switches distribute input cells to appropriate output lines. The system also includes selectors for switching the ATM cell switches in accordance with a selection signal that is output from an external system. The ATM switches output an idle cell when there is no cell to be output. When the selector judges that it is necessary to switch the systems as indicated by the change-over signal, the selector switches the system after it confirms that an idle cell is output from both ATM cell switches. The idle cell that is output indicates that there is no cell stored in either system; thus, it is easy to switch the systems without causing the duplication or omission of a cell.

Abstract: A cell exchanging apparatus which distributes cells input through a plurality of input lines to output lines by destination for output. Without stopping the operation of the cell exchanging apparatus, active and standby cell switches of the cell exchanging apparatus can be changed over. The cell exchanging apparatus comprises a first and second cell switches, input selectors for feeding input cells only to either of the first and second cell switches, and output selectors for outputting cells output from either of the first and second cell switches to an external system. When a change-over is instructed by a system change-over signal, the input selectors start to feed input cells into the cell switch in the standby mode. When detecting completion of cell output operation from the active cell switch, the output selectors select a new active cell switch.