Block Selection Panel

The block selection panel is rather complicated. At the bottom, block time width is set by sliding the control until the required time shows. The number of samples this includes will depend on the sample rate. Similarly, pre-event interval may be set. These controls cannot be set by typing directly into the numeric panels.

The 'Set Blocks Relative to Events' section directly above the block time width panels is designed to allow blocks to be automatically created by scanning through an event channel and picking up particular levels. Above the block time width panel is a section which allows event levels to be specified. The sliders should be used to generate a number or list of numbers in the text panel.

 To the right of this area, a panel allows the number of blocks generated for each event to be set. It is important to understand the difference between events and blocks. Events may also coincide with 'trials', whereas blocks are just 'time epoches' in the record, and may or may not be exactly synchronised with events. For example, if we set the number of blocks per event to 4, and block width is 15 seconds, it means that the first block will start coincident with the event (taking into account the pre-event interval), the second will start exactly 15 seconds later, the third will start at the end of the second (30 seconds) and the fourth will start after that (45 seconds).

The other controls are generally self explanatory. The 'Deep search' switch needs to be checked if the event is of short duration (less than 20 samples long, in this case <1 second). Otherwise the event detection system will only look at each tenth point, which speeds up the event channel scan (if it finds a change, it then tracks back to get the exact time).

When all the block settings are OK, click the 'View Blocks' button. The system will scan for blocks, and as long as it finds some it will require that the settings you selected are stored in a Block file. Any file name may be given, the extension .BLO is automatically added. The block system only prompts for this file name if Macro Record is on, however block settings can be recorded at any time if required using the File menu in the block settings panel. When the file has been saved, the block panel closes, a Multiblock Review appears and a new line is generated in the macro, e.g. ' Review#1,SetBlocks@C:\CPI\YOURNAME.BLO'.