In DG4062 spec,rise time for square is less 12ns(1Vpp),but for arbitrary is less 5ns, and not definite rise time for pulse?I think if you use higher bandwidth scope like 1GHz above to measure,you should get the precise value.
When I using TDS1012 to measure sync of 33120A,the fall time is around 3.5ns, but when using SDA760Zi, it changed to 700ps.