When to use clock recovery for rise time on MSO4 series?

I noticed that under the measurement for rise time on the MSO 4 series, there is an option to use clock recovery.  Can you provide an example of when I would use this option?

Hi Frank,<br> <br> The clock recovery option is meant for testing the rise time of a serial bus, limiting the measurement to transition bits.

<p>Thanks for the reply, but I'm still a bit confused.&#160; Wouldn't all the transitions on the data line be transition bits and thus not need the clock?&#160; Can you provide a concrete&#160;example of when clock recovery would be needed?</p> <p></p>

Transition bits are those which go from one digital state to the other and then back in the least amount of clock cycles possible (2 clock cycles).<br> <br> As an example, for rise time, the transition bits would be those that meet a 1 0 1 pattern.<br> A 1 0 0 1 pattern would not meet this definition and so would be excluded from the measurements. 1 0 1 1 would as that meets the 1 0 1 pattern (what comes after does not matter).<br> <br> These transition bits are often the most testing (aka worst case) of a system and so there's particular interest in measuring them.