Datasheet

Clock Crystals
7–326
2.6 Clock Crystals
Clock frequency is controlled by the clock-driver card and is limited by
clock-control components to 100 MHz. The GTLP receiver device is used in
a latched mode of operation, so GTLP data frequency is equal to one-half the
clock frequency. Clock crystals and spares, in frequencies of 66 MHz, 75 MHz,
87 MHz, and 100 MHz, are included with the kit. One crystal can be installed
on each clock card, with the others stored in the clock-crystal tube (see
Figure 2–11).
Figure 2–11.Clock Crystal on Card (Left) and Stored in Tube (Right)
If you plan to store the clock-driver card with the crystal installed, insert the
crystal far enough so that the leads barely protrude on the opposite side (see
Figure 2–12). This prevents bending the leads if they catch on the foam when
the card is placed in the case.
Figure 2–12. Clock Crystal With Leads in Position for Storage