Main oscillograph function index

A lot of oscillograph function index can affect the performance of appearance significantly, affect the ability of accurate test parts of an apparatus then. This section will introduce the ABC of these index. These content still will help you be familiar with oscillograph term, let you make wise decision when choosing the oscillograph that suits most.

Bandwidth

Bandwidth is a character with the mainest oscillograph, because it indicated the frequency domain range of oscillograph. Change character, it decided can accurate the signal range that show and tests (in frequency respect) . Bandwidth is an unit with Hz. If bandwidth is insufficient, oscillograph cannot accurate show concrete signal. For example, the extent of signal may be incorrect, the brim may be unsharpness, undee detail may be missing. The bandwidth of oscillograph is the lowermost frequency when inputting signal attenuation 3dB. Still a kind of method can use examine bandwidth: If you input wave of a pure sine in oscillograph, the extent that bandwidth shows namely is the 70.7% when the smallest frequency of concrete signal extent.

Connect number of channels

What the passageway points to is the independent input end of oscillograph. The amount of oscillograph passageway is in normally 2 to 20 between. There are 2 below the circumstance normally or 4 passageways. The signal type that the passageway bears the weight of is different also. Certain oscillograph counts word passageway only (these appearance are called DSO, namely digital signal oscillograph) . Still a few is call to mix signal oscillograph (MSO) , they have imitate channel already, have digital channel again. For example, MSO of Keysight InfiniiVision series has 20 channels, among them 16 are digital passageway is mixed, 4 are imitate passageway. Ensure the application that enough passageway is used at you is crucial. If have two channels, but need shows 4 signal at the same time, can appear apparently problem.

Sampling rate

The sample that the sampling of oscillograph is led even if every second can collect oscillograph is counted. The sampling rate of proposal oscillograph should achieve 2.5 times of its bandwidth at least. Nevertheless, below good case, sampling rate should achieve bandwidth 3 times or taller. When the sampling that evaluation oscillograph alleges leads technical index, need is careful all the more. The sampling rate that manufacturer can achieve oscillograph normally calls rate of the biggest sampling, but occasionally rate of this the biggest sampling is using only or the ability when two passageways may be achieved.

If use more channel at the same time, sampling rate can be reduced possibly. Accordingly, it is OK when maintaining designation the biggest sampling to lead that you had better affirm use how many channel. If the sampling rate of oscillograph is too low, the signal that you see on oscillograph is met not quite accurate. For example, if want to examine weaveform, but sampling rate is inferior, every cycle can generate oscillograph only two are nodded (graph 26) .

To same undee, after sampling rate increases, every cycle is OK sampling 7 (graph 27) . Apparent, number of every second sampling is larger, weaveform shows clearer, more accurate. If we raise undee sampling rate ceaselessly in afore-mentioned give typical examples, final sampling dot is successive almost it seems that. In fact, oscillograph connects regular meeting to use Sin between sampling dot (X) / X interpolation.

Memory deepness

The place before be like is narrated, digital oscillograph uses A/D (modulus) converter will digitlize input weaveform. Next, the data after digitlization memory is in the high speed memory of oscillograph. Memory deepness is to point to exact can store how many example or dot, and can store how long. Memory deepness is having main effect to the sampling rate of oscillograph. Below good case, no matter oscillograph uses what setting, sampling rate can keep constant.

Nevertheless, this kind of oscillograph needs vast storage space, the time with ability great implementation / reseau setting, cost is so high, can serious effect and restrict can the amount of the have client of the burden. Conversely, sampling rate can be reduced as the addition of time limits. Memory deepness is very important, because the memory deepness of oscillograph is bigger, can capture below complete sampling speed undee time is longer.

Will look from mathematical meaning, can convey this with the formula below: Memory deepness = (sampling is led) * (indication time) accordingly, if want to observe with high resolution two length is periodic, need deep memory. Additional, when oscillograph uses deepness of the deepest memory to install, the response that checks oscillograph function is very main also. Below this kind of mode, the weaveform of oscillograph captures rate function can drop badly normally, accordingly, a lot of engineers just are using deep memory when necessary only.

Weaveform captures rate

Weaveform captures leading is the rate that shows oscillograph can be collected and newer weaveform shows. Although look in person eye, what oscillograph shows is " real time " undee, but because newer rate is too rapid,this is, person eye cannot sense change. Actually, collect in weaveform between existing time of a few dead band (graph 28) . Inside this paragraph of silent time, the weaveform of one part did not show go up in oscillograph.

Accordingly, if a certain still always produced amid a few unusual event or burr, you will not see it. Can see from this, fast weaveform captures rate why very important. Weaveform captures rate is rapidder, dead band time is shorter, this is meant capture the probability of unusual event or burr is higher. For example, assume you are showing every 50000 periodic ability appear the signal of burr. If the weaveform of oscillograph captures,lead for every second 100000 weaveform, so you are average every second can capture this burr two.

Conversely, if the weaveform of oscillograph captures,lead for every second 800 weaveform, need ability so on average one minute to capture. This viewing time is too long. Capture to weaveform rate technology index, need to be read carefully. A few manufacturer need to use specific collection the weaveform that mode ability achieves his to publicize captures rate technology index. These collect mode to may restrict oscillograph badly to rebuild in rate of memory deepness, sampling and weaveform the function that waits for a respect. Accordingly, capture with the biggest weaveform when oscillograph when leading indication weaveform, best check looks up oscillograph to be in right now function.