A&D Series 57ZZ Bedienungsanleitung PDF herunterladen (Seite 22)

zero volts. Figure 29 illustrates this difference. The

AC coupling setting is handy when the entire signal

(alternating plus constant components) is too large

for the volts/div setting.

The ground setting disconnects the input signal from

the vertical system, which lets you see where the

zero-volt level is on the screen. With grounded input

coupling and auto trigger mode, you see a horizontal

line on the screen that represents zero volts.

Switching from DC to ground and back again is a

handy way of measuring signal voltage levels with

respect to ground.

Bandwidth Limit

Most oscilloscopes have a circuit that limits the

bandwidth of the oscilloscope. By limiting the band-

width, you reduce the high-frequency noise that

sometimes appears on the displayed waveform,

providing you with a more refined signal display.

Alternate and Chop Display

On analog scopes, multiple channels are displayed

using either an alternate or chop mode. (Digitizing

oscilloscopes can present multiple channels simulta-

neously without the need for chop or alternate

modes.)

Alternate mode draws each channel alternately – the

oscilloscope completes one sweep on channel 1,

then one sweep on channel 2, a second sweep on

channel 1, and so on. Use this mode with medium-

to high-speed signals, when the sec/div scale is set to

0.5 ms or faster.

Chop mode causes the oscilloscope to draw small

parts of each signal by switching back and forth

between them. The switching rate is too fast for you

to notice, so the waveform looks whole. You typi-

cally use this mode with slow signals requiring

sweep speeds of 1 ms per division or less. Figure 30

shows the difference between the two modes. It is

often useful to view the signal both ways, to make

sure you have the best view.

Figure 29. AC and DC input coupling.

Figure 30. Multi-channel display modes.

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A&D Series 57ZZ Bedienungsanleitung Seite 22