Patent ID: 8406269

Claim:
A field bus system comprising: a plurality of users ( 10 , 20 , 30 ), including a local user ( 10 ), a first adjacent user ( 30 ), and a second adjacent user ( 20 ), each having a first clocked transmitter ( 16 ) and a first clocked receiver ( 17 ) for transmitting data signals to the first adjacent user ( 30 ) or for receiving data signals from the first adjacent user ( 30 ); the local user ( 10 ) having a second clocked transmitter ( 12 ) and a second clocked receiver ( 14 ) for transmitting data signals (DI 2 ) to the second adjacent user ( 20 ) and for receiving data signals (DO 2 ) from the second adjacent user ( 20 ); and each specific spread spectrum clock ( 40 ) being assigned to and specific for each user ( 10 , 20 , 30 ) for providing a user-specific spread spectrum clock signal which is sent to the transmitter ( 16 ) and the receiver ( 17 ) of the particular user ( 10 , 20 , 30 ) to allow data signals (DO 1 , DI 1 , DO 2 , DI 2 ) to be transmitted and received synchronously with the specific spread spectrum clock signal, the local user ( 10 ) transmitting its specific spread spectrum clock signal (SST 1 ) to the first adjacent user ( 30 ), and this spread spectrum clock signal (SST 1 ) being used by the first adjacent user ( 30 ) for receiving and for transmitting to the local user ( 10 )), the specific spread spectrum clock signal of the second adjacent user ( 20 ) being sent to the second transmitter ( 12 ) and to the second receiver ( 14 ) of the local user ( 10 ).