One, introduce

When the consideration buys new oscillograph, the user often can raise a lot of questions. For instance, which kinds of oscillograph ought to choose? Need much wider bandwidth? Can imitate oscillograph satisfy the job to need? Still need a DSO? The question that another people often asks is: "Can DSO satisfy my job to need? "In other words, can DSO finish all measurement that what what I make with imitate oscillograph so to work?

Regretful is right all these problems and the answer with concise neither one. The answer of the problem depends on completely the signal that the measurement that should undertake works and should measure. Below some circumstances imitate oscillograph compares existing DSO to be close friends, let us inspect a certain number of main reflection now principle.

2, simple repeatability signal

Use imitate oscillograph and DSO can observe simple repeatability signal well normally. But both has its advantage and limitation. To imitate oscillograph, because the twilight time of CRT is very short, be hard to show the signal with very low frequency consequently. Because the brightness sweeping mark on oscilloscope tube and scanning speed become inverse ratio, have so rise quickly, of decay time low repeat rate signal to see very hard. And the brightness sweeping mark of DSO and scanning speed and signal repeat rate to have nothing to do. As circumstance of the signal that be measured different, this characteristic may be an advantage also may be defect.

Have to showing enough tall for the fast edge of the repeatability signal that repeats rate, what doesn't the function of DOS and imitate oscillograph have to distinguish almost. With two kinds of oscillograph can very good observation signal is undee. When wanting to undertake the measurement of signal parameter, the advantage of DSO depends on having the capacity that gauges automatically. And when use imitate oscillograph, user must oneself install cursor, analysis to understand indication undee ability to get metrical

Result.

If want to undertake adjustment the job, had better use imitate oscilloscope commonly so. Because the real time of imitate oscillograph shows ability makes it can show the tension of the input in every hour,this is. Its weaveform replaces rate (per sec. is painted on screen the frequency that sweeps mark) very tall, scanning can pass 100000 times with Yuan Chao when tall scanning speed / second. So any change of signal can be shown instantly come. And the formal performance that a little consular change is showing change with undee brightness on screen comes out.

As contrary as imitate oscillograph, what DSO place shows is the weaveform that rebuilds with collection undee data. Per sec. collects weaveform show number far under 100. On some oscillograph, per sec. collects undee Lou Fachao to go 5 times. The signal that the result changes in signal happening and changed is shown on screen come between had apparent time delay. When undertaking adjustment the job to the system, this is the major drawback of use DSO.

3, mixedder repeatability signal

Signal of afore-mentioned simple repeatability can be gotten in a lot of electronics see inside the country, but these signal often use the carrier that serves as information. For this the purpose can have a variety of forms, for example sine wave, swim strong, inclined wave or wave of a flight of stairs, and a variety of modulation signal often may be used at the same time with a variety of modulation means.

The example of a common complex imitate signal is composite signal. This signal by a variety of different frequency, the heft of distinct range is formed, include pulse already, also include sine wave, had another sine wave of phase shift to represent chromatic news at be being added. To such circumstance, imitate shows the DSO of wave be disgusted with to have its oneself special advantage, can undertake to the different share of signal optimal section observes severally.

For example, imitate oscillograph is provided defend oneself finitely the scanning number with rate and very high per sec. , it can show what weaveform stops in time to promulgate the direct ratio of this degree of change on undee scanning is in at signal some is specific persistent time, this very good case that shows chromatic modulation.

Because oscillograph has very tall weaveform to replace rate (scanning number of seconds is very high) , so it can show the fruit that undertakes adjustment to the system instantly. When use DSO, because its sampling check the number is limited and the change that does not have brightness, make information of a lot of undee detail cannot be shown come, although some of DSO may be had two go up or many brightness administrative levels, but the distinction that this just gets on relative to the meaning, plus the indication resolution with finite oscillograph, make it still cannot reproduce the result that imitate shows. (graph 1) the circumstance that gave out to use imitate oscillograph to show composite signal. The undee detail that notices to be abounded among them please and the circumstance that brightness changes. (graph 2) those who give out is the case that identical signal shows on the CRT of typical grating scanning in DSO

If want to show the fraction of signal of a video only, for example the TV in specific travel sends some data of TV of article of test signal, graph or some is specific the pulse picking color that goes up all right group, so best DSO. If use imitate oscilloscope, repeat rate as a result of comparative and inferior signal, plus the time of signal part itself that wants observation very short, bring about indication picture very easily too dark and see hard. And DSO criterion no matter the repetition of signal rate discretion has consistent brightness, consequently can with very tall this degree shows this signal. If there still are aiguille or burr in the dilettante form of repeatability, so it is impossible to see these that use imitate oscillograph watchs whole wave form of peak or kind of burr. And when DSO, it is OK that use peak value detects these aiguille show place come out (see a picture 3) .

4, blame repeatability signal and twinkling change

Previously, because observe very difficult and price is exorbitant, so signal of repeatability of blame of a lot of observation and transient work to must be made Nuo, because be in at that time, observe this kind signal needs to use costly imitate memory oscillograph, camera and long twilight oscilloscope tube to wait.

If certain incident happens only, so imitate oscillograph is normally cannot payable. And this is DSO reveals his the opportunity of powerful ability, DSO can take this kind of unusual one-time event, and the hope according to yours shows it for long come out. This kind of unusual event may be the result of interference even, through using molestation itself sparks, DSO is had demonstrate the ability that touchs breath of post a letter beforehand, include to show the account of interference. Graph 4 those who show is receive the microphonic effect weaveform in the cable when bouncing on the desktop when the open a way of cable one aspect of the matter, spark in the graph always express with 螖 symbol, the undee information of this symbol left touchs post a letter to cease beforehand namely.

5, imitate oscillograph, number oscillograph, or both has both

We had seen, in routine technical personnel needs imitate oscillograph and digital memory oscillograph at the same time, so that to them the signal that encounters in the job has best observation, in certain application circumstance imitate oscillograph is compared appropriate, and in DSO of another some of circumstance it is better choice. A few DSO that see on the market are so-called the outward appearance that has " imitate oscillograph and sensory " . But these are dinkum DSO, although among them the control orgnaization of a few oscillograph is arranged,be gotten and a lot of imitate oscillograph are identical, and have very tall scanning a few more additionally to be led newlier again in order to imitate the ability of true imitate oscillograph.

Or, they may have very high sampling rate and the record length that collects weaveform is very finite, do not have observation to compare mixed signal thereby, prevent the time resolution that place of signal of occurrence false appearance needs, of course, these oscillograph have the advantage of DSO not only, also have all drawback of DSO. Those who be worth to rejoice is, there is a kind of oscillograph now can the ability with a true imitate oscillograph and both DSO and advantage union at an instrument. This combines oscillograph namely, assorted oscillograph combines oscillograph of a high-powered imitate together, and very can easy from a kind working mode changes pattern of another kind of job.

Technical personnel chose assorted oscillograph to be meant, should have this oscillograph only enough shame, without giving thought to his working requirement how, his at hand always has appropriate tool. When this instrument installs DSO, the user can undertake automatic parameter with it, measure, the weaveform that puts lay aside to collect is made then take an examination of shellfish forcedly; And at the same time, when need ground time still can have the infinite resolution of imitate oscillograph and familiar and authentic weaveform to show, when and use combining oscillograph, no matter signal repeats the discretion of rate, can obtain the brightest indication, in other words, the elite that assorted oscillograph uses imitate oscillograph and DSO are bothly has both at a suit.