| 摘要 |
PURPOSE:To simulate colliding state under actual environment without changing the characteristic of a transmission line and a transceiver by sending immediately a collision generating signal for a prescribed time on a transmission line after detection of a packet and controlling the signal with external designation. CONSTITUTION:A packet detection circuit 1 inputs a reception signal from a transceiver to detect the transmission of a packet on the transmission line. This function is a carrier sense function being one of basic function of the carrier sense multiple access/collision detect (CSMA/CD) system, it is realized by the level detection of an input signal and the level is at binary '1' when the packet is received and the level is at binary '0' when no packet is received. The output of the packet detection circuit 1 is inputted to a collision state generation control circuit 2 and an AND circuit 3. The circuit 2 changes the output to binary '0' or binary '1' according to an external program every time the output is changed from binary '1' to binary '0', and when the circuit 1 detects the packet end.
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