Execution of set of commands for a fixed period of time, but at different time instants

consider my time frequency is 50hz, i divide this time into 3 time intervals such that ta+tb+tc= ts, ts=1/50hz . i have to pass certain command for ta duration, then certain commands for tb, and tc too.

how can i write program for such execution..

please some help me

Answer 1

[Walter Roberson]

mod(time, 1)*150 and use logical indexing <50, >=50 <100, >=100