QUICK EYE-DIAGRAM SCAN A DDR memory interface can be made up of many DQ (data) channels. For instance, a DDR DIMM (dual-inline memory module) consists of 64 DQ channels that equal 64 bits or 8 bytes.

An eye-pattern diagram is a good method for quickly visualizing and accurately measuring timing jitter (see the figure, b). Typical communications applications usually seek a BER of about 1 × 10 ...