Agilent Technologies Infiniium 8000A, Руководство программиста

Страница: 746 / 934

29-38
Advanced State Trigger Mode and Commands
Logic triggering is similar to the way that a logic analyzer captures data.
This mode is useful when you are looking for a particular set of ones and
zeros on a computer bus or control lines. You determine which channels
the oscilloscope uses to form the trigger pattern. Because you can set
the voltage level that determines a logic 1 or a logic 0, any logic family
that you are probing can be captured.
There are two types of logic triggering: Pattern and State. The difference
between pattern and state triggering modes is that state triggering uses
one of the oscilloscope channels as a clock.
Use state triggering when you want the oscilloscope to use several
channels as the trigger source, with one of the channels being used as a
clock waveform.
The State trigger identifies a trigger condition by looking for a clock edge
on one channel and a pattern on the remaining channels. A pattern is a
logical combination of the remaining channels. Each channel can have
a value of High (H), Low (L) or Don’t Care (X). A value is considered a
High when your waveform's voltage level is greater than the trigger level
and a Low when the voltage level is less than the trigger level. If a channel
is set to Don’t Care, it is not used as part of the pattern criteria. You can
select the clock edge as either rising or falling.
The logic type control determines whether or not the oscilloscope will
trigger when the specified pattern is found on a clock edge. When AND
is selected, the oscilloscope will trigger on a clock edge when input
waveforms match the specified pattern. When NAND is selected, the
oscilloscope will trigger when the input waveforms are different from the
specified pattern and a clock edge occurs.
Available trigger conditioning includes HOLDoff and HYSTeresis (Noise
Reject).