User`s guide

13 Digital Channels
388 InfiniiVision Oscilloscopes User’s Guide
reconstructed waveforms, they do not show ringing and perturbations. You will not find
ground problems through examination of the waveform display. In fact, it is likely you will
discover the problem through random glitches or inconsistent data measurements. Use
the analog channels to view ringing and perturbations.
Best Probing Practices
Because of the variables L, di, and dt, you may be unsure how much margin is available in
your measurement setup. The following are guidelines for good probing practices:
• The ground lead from each digital channel group (D15–D8 and D7–D0) should be
attached to the ground of the device under test if any channel within the group is
being used for data capture.
• When capturing data in a noisy environment, every third digital channel probe’s
ground should be used in addition to the channel group’s ground.
• High-speed timing measurements (rise time < 3 ns) should make use of each digital
channel probe’s own ground.
When designing a high-speed digital system, you should consider designing dedicated
test ports that interface directly to the instrument’s probe system. This will ease
measurement setup and ensure a repeatable method for obtaining test data. The
01650-61607 16-channel logic probe and termination adapter is designed to make it easy
to connect to industry-standard, 20-pin board connectors. This probe consists of a 2 m
logic analyzer probe cable and a 01650-63203 termination adapter that provides the
proper RC networks in a very convenient package. Three 20-pin, low-profile, straight
board connectors are included. Additional board connectors can be ordered from Agilent
Technologies.