Thanks for all the replies, I will check out the links.
In response to the qus:
1) The servo requires pulses varying from 75-225ms, and I will need 10 changes at 60 second intervals, but it has to stay in the same place until then.
2) As soon at it reaches the end, it need to go back to the start (repeating)
3) Futuba S3003, I think it may be digital
MikeMI:
It's my own little project, not for any RC vehicles.
The pulse length needs to change- but there needs to be a pulse every 20ms- so the frequency can stay the same
EDIT: Perhaps there is a way to change the resistance over time. If I change R2, then the mark time would increase- but the space time would stay the same - this would be the easiest configuration.