The different synchronization options | Synchronization (Option) |
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Synchronization (Option)
This option allows the connection of multiple boards to generate a
If no synchronization is desired for a certain board you can exclude it by setting the register shown in the following table. This must be done seperately for every board that should not work synchronized.
Register | Value | Direction | Description | |
SPC_COMMAND | 0 | r/w | Command register of the board | |
| SPC_NOSYNC | 120 | Disables the synchronization globally. | |
The different synchronization options
Synchronization with option cascading
With the option cascading up to four Spectrum boards can be synchronized. All boards are connected with one synchronization cable on their
As the synchronization lines are organized as a bus topology, there is a need for termination at both ends of the bus. This is done in factory for the both
When synchronizing multiple boards, one is set to be the clock master for all the connected boards. All the other boards are working as clock slaves. It’s also possible to temporarily disable boards from the synchronization.
The same board or another one of the connected boards can be defined as a trigger master for all boards. All trigger modes of the trigger master board can be used. It is also possible to synchronize the connected boards only for the samplerate and not for trigger. This can be useful if one generator board is continuously generating a test- pattern, while the connected acquisition board is triggering for test results or error conditions of the device under test.
For the fact that the termination is set in factory the order of the syncronized boards cannot be changed by the user. Please refer to the boards type plate for details on the board’s termination. End boards are marked with the option
When the boards are synchronized by the option cascading there will be a delay of about 500 ps between two adjacent boards.
The figure on the right shows the clocks of three cascaded boards with two channels each, where one end-board is de- fined as a clock master. Slave 1 is therefore a middle-board and Slave 2 is the other end-board. The resulting delay be- tween data of the two end-boards is therefore about 1 ns.
Please keep in mind that the delay between the channels of two boards is depending on which board is actually set up as the clock master and what boards are directly adjacent to the master.
Synchronization with option starhub
With the option starhub up to 16 Spectrum boards can be synchronized. All boards are connected with a seperate synchronization cable from their
When synchronizing multiple boards, one is set to be the clock master for all the connected boards. All the other boards are working as clock slaves. It’s also possible to temporarily disable the synchronization of one board. This board then runs individually while the other boards still are synchronized.
The same board or another one of the connected boards can be defined as a trigger master for all boards. All trigger modes of the board defined as the trigger master can be used. It is also possible to synchronize the connected boards only for the samplerate and not for trigger. This can be useful, if one generator board is continuously generating a testpattern, while the connected acquisition board is triggering for test results or error conditions of the device under test.
Additionally you can even define more than one board as a trigger master. The trigger events of all boards are combined by a logical OR, so that the first board that detects a trigger will start the boards. This OR connection is available starting with starhub hardware version V4.
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