A&D Series 57ZZ Manual do Utilizador descarregar pdf (Página 16)

Frequency Response

Bandwidth alone is not enough to ensure that an

oscilloscope can accurately capture a high frequency

signal. The goal of oscilloscope design is to have

Maximally Flat Envelope Delay (MFED). A

frequency response of this type has excellent pulse

fidelity with minimum overshoot and ringing. Since

a digitizing oscilloscope is composed of real ampli-

fiers, attenuators, ADCs, interconnect and relays, the

MFED response is a goal which can only be

approached. Pulse fidelity varies considerably with

model and manufacturer.

Vertical Sensitivity

The vertical sensitivity indicates how much the

vertical amplifier can amplify a weak signal. Vertical

sensitivity is usually given in millivolts (mV) per

division. The smallest voltage a general purpose

oscilloscope can detect is typically about 1 mV per

vertical screen division.

Sweep Speed

For analog oscilloscopes, this specification indicates

how fast the trace can sweep across the screen,

allowing you to see fine details. The fastest sweep

speed of an oscilloscope is usually given in nanosec-

onds/div.

Gain Accuracy

The gain accuracy indicates how accurately the

vertical system attenuates or amplifies a signal. This

is usually listed as a percentage error.

Time Base or Horizontal Accuracy

The time base or horizontal accuracy indicates how

accurately the horizontal system displays the timing

of a signal. This is usually listed as a percentage

error.

Sample Rate

On digitizing oscilloscopes, the sample rate indicates

how many samples per second the ADC (and there-

fore the oscilloscope) can acquire. Maximum sample

rates are usually given in megasamples per second

(MS/s). The faster the oscilloscope can sample, the

more accurately it can represent fine details in a fast

signal. The minimum sample rate may also be

important if you need to look at slowly changing

signals over long periods of time. Typically, the

sample rate changes with changes made to the

vertical sensitivity control to maintain a constant

number of waveform points in the waveform record.

ADC Resolution (or Vertical Resolution)

The resolution, in bits, of the ADC (and therefore the

digitizing oscilloscope) indicates how precisely it

can turn input voltages into digital values.

Calculation techniques can improve the effective

resolution.

Record Length

The record length of a digitizing oscilloscope indi-

cates how many waveform points the oscilloscope is

able to acquire for one waveform record. Some digi-

tizing oscilloscopes let you adjust the record length.

The maximum record length depends on the amount

of memory in your oscilloscope and its ability to

combine memory length from unused channels.

Since the oscilloscope can only store a finite number

of waveform points, there is a trade-off between

record detail and record length. You can acquire

either a detailed picture of a signal for a short period

of time (the oscilloscope “fills up” on waveform

points quickly) or a less detailed picture for a longer

period of time. Some oscilloscopes let you add more

memory to increase the record length for special

applications.

Waveform Capture Rate

Waveform capture rate is the rate at which an oscil-

loscope triggers, acquires, and displays waveforms.

On DSOs, the rate is a few hundred times per second

at the most, due to their serial processing architec-

ture. All in all, most DSOs sample about 1% of the

total time the signal is available to them. The limita-

tion of this approach is that signal activity continues

even though the oscilloscope isn’t sampling very

often. And an important waveform aberration might

occur during that lapse. A new digitizing oscillo-

scope architecture, the DPO, has emerged to solve

this problem. On a DPO, signal acquisition is

repeated hundreds of thousands of times per second

– as fast as an analog oscilloscope. The DPO’s

extremely high waveform capture rate (as well as

their digital phosphor technology) makes it possible

to view rare, erratic signal events.

1 2 ... 11 12 13 14 15 16 17 18 19 20 21 ... 43 44

Comentários a estes Manuais

Sem comentários

A&D Series 57ZZ Manual do Utilizador Página 16

Comentários a estes Manuais

Manuais e produtos relacionados com Medição, teste e controlo A&D Series 57ZZ