Synchronize y and x axes of 2 subplots

Hi,

ich have one figure containing two subplots. Subplot 1 has arbitrary ticks/labels on its x axis and the time on its y axis. Subplot 2 is another representation of Subplot 1. In this case the y axis is arbitrary. The x axis, however, displays the time.

My objective is to link both time axes (the y axis of Sp1 and the x axis of Sp2) so that ticks/ticklabels and the limits are the same.

Do you guys know a way to tackle this problem?

Cheers, beari