Circuit arrangement for testing a passive bus network with the carrier sense multiple access with collisions detection method

Claim 1

A circuit arrangement for testing a passive bus network system which comprises a plurality of stations each connectible to a coaxial cable segment via a respective media adapter unit, the stations operable for data packet exchange via the coaxial cable segment in accordance with the carrier sense multiple access with collision detection access method to detect a collision state and a heartbeat state, said circuit arrangement comprising: a data transmitter including a first amplifier unit means comprising an output coupled DC free to the respective media adapter unit and an input, a data packet generator including a resonator and a trigger circuit connected to said resonator for generating data packets with a defined bit rate, an external data input for receiving data packets having an arbitrary data packet pulse sequence and an arbitrary bit rate, and a switch connected to said input of said first amplifier unit means and operable to selectively connect said data packet generator and said external data input to said first amplifier unit means; a data receiver including a first amplifier means including an input coupled DC free to the respective media adapter and an output, second amplifier means including a first input connected to said output of said first amplifier means, a second input and an output, a data output, third amplifier means including an input connected to said output of said second amplifier means and an output connected to said data output, and a first threshold circuit including an input connected DC free to the respective media adapter unit and an output connected to said second input of said second amplifier means and operable to suppress noise pulses; and status receive means including first amplifying stage means including an input coupled DC free to the respective media adapter unit and an output, second amplifying stage means including a first input connected to said output of said first amplifying stage means, a second input and an output, a second threshold circuit including an input coupled DC fill to the respective media adapter unit and an output connected to said second input of said escond amplifying stage means and operable to suppress noise pulses; and status receive means operable to monitor the data packet reception with respect to the collision state and the heartbeat state producing respective collision and heartbeat signals and further comprising a collision display device, a heartbeat display device, a collision output, a decision stage connected between said output of said first amplifying stage means and said output of said second amplifying stage means and said collision display device and heartbeat display device, and a third amplifying stage means including an input connected to said output of said second amplifying stage means and an output connected to said collision output.