Hi Elise,
I believe you want to modify the Time Interval to be 0.2 seconds(or 200 milliseconds) uniformly, for that please utilize the setuniformtime method of timeseries object. Refer the following code snippet:
ts1out = setuniformtime(ts1, 'Interval', 200) % Setting the Interval to be 200ms, which is equal to 0.2s
Hope this helps!