A&D Series 57ZZ Bedienungsanleitung PDF herunterladen (Seite 26)

In practice, you will probably use both modes:

normal mode because it lets you select just the signal

area you need to see, and auto mode because it

requires less adjustment.

Some oscilloscopes also include special modes for

single sweeps, triggering on video signals, or auto-

matically setting the trigger level.

Trigger Coupling

Just as you can select either AC or DC coupling for

the vertical system, you can choose the kind of

coupling for the trigger signal.

Besides AC and DC coupling, your oscilloscope may

also have high frequency rejection, low frequency

rejection, and noise rejection trigger coupling. These

special settings are useful for eliminating noise from

the trigger signal to prevent false triggering.

Trigger Holdoff

Sometimes getting an oscilloscope to trigger on the

correct part of a signal requires great skill. Many

oscilloscopes have special features to make this task

easier.

Trigger holdoff is an adjustable period of time during

which the oscilloscope cannot trigger. This feature is

useful when you are triggering on complex wave-

form shapes, so that the oscilloscope only triggers on

the first eligible trigger point. Figure 36 shows how

using trigger holdoff helps create a usable display.

Digitizing Oscilloscope Triggers

In addition to the usual threshold triggering, many

digitizing oscilloscopes offer a host of specialized

trigger settings which have no equivalents on analog

instruments. These triggers respond to specific

conditions in the incoming signal, making it easy to

detect, for example, a pulse that is narrower than it

should be. Such a condition would be impossible to

detect with a voltage threshold trigger alone.

Following is a partial list of the digital triggers found

on advanced DSOs and DPOs, along with a brief

definition of each:

• Pulse Width and Glitch trigger

Detects pulses either within or exceeding speci-

fied widths.

• Runt Pulse trigger

Detects a pulse that crosses the lesser but not the

greater of two threshold levels.

• Logic (Boolean) trigger

Uses multiple oscilloscope inputs as binary

inputs that must meet logical conditions such as

NAND or NOR to produce a trigger.

• Serial Data trigger

Detects specific data combinations in digital

telecom signals

• Setup and Hold Violation trigger

Detects violations of digital setup and hold time

when clock and data signals are acquired on two

different inputs.

Figure 36. Trigger holdoff.

1 2 ... 21 22 23 24 25 26 27 28 29 30 31 ... 43 44

Kommentare zu diesen Handbüchern

Keine Kommentare

A&D Series 57ZZ Bedienungsanleitung Seite 26

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Messen, Testen & Steuern A&D Series 57ZZ