The rate of the Sample Clock is equal to (frequency of Sample Clock Timebase) / (value of this property).

If the Sample Clock Timebase is not a periodic clock, the value of this property determines the number of Sample Clock Timebase edges that the device must receive before producing each Sample Clock pulse. Use Active Edge to specify the polarity of these edges.

Setting this property has a similar effect to setting Rate. Use Rate when you know the rate of the Sample Clock Timebase and you want to acquire or generate samples at the specified rate. Use this property when you have an external timebase that you want to divide down and use as the Sample Clock, but you do not know rate of the external timebase.