Development of circuit of 80 time number is very rapid, and its check a tool -- digital oscillograph also resembles emerge. Because digital oscillograph price is more expensive than imitate oscillograph much, so we must press need when choosing digital oscillograph and decide, cannot blind seeks tall target, can bring otherwise very the waste of friend.
The digital oscillograph price of a low class, high quality scales differs nearly 50 times (8000 yuan - many yuan 50) .
For example: The LC584AXL of interest of American auspicious issue
of USD of of of 16M of of of 8Gs/s of of of 1GHz of 4ch forty-seven thousand and fifty
of USD of of of 1K of of of 20M/s of of of 20Mhz of 2ch 800
How does the choice just calculate reasonable?
1, bandwidth
If need to measure bandwidth accurately,choose and highest be measured the relation of signal frequency, we see a case below first: Have the pulse signal of a 50MHz for example:
From above in light of the graph that the oscillograph of different bandwidth measures, rise to make sure test signal extent is mixed the precision that delay, the 3-5 that the bandwidth of choice oscillograph should be frequency of the signal that be measured times, measure accurately want 8-10 times or above.
2, pick sample book
Sine wave: Be more than 5 sampling to nod / periodic (general requirement) , sampling dot is close to more more more actually undee.
Pulse: Ascendant edge should be more than 5 sampling dot:
Measure ascendant edge accurately to want to be more than 10 sampling dot.
3, store length: Store length ＝ collects *10 of speed of example * scanning, also can saying is undee observation time, formulary
4, spark function: Should ensure can capture and synchronism is measured signal. Be measured at observation and analysis with benefit undee.
Spark means has 3 kinds: Spark automatically, normal sparks, odd second spark.
Spark kinds functional fraction is large:
1) the brim (Edge) spark: All digital oscillograph have, it is edge of point out mistakes so that they can be corrected, negative edge sparks, window sparks, before spark and post-trigger.
2) sagacity (Smart) spark: Consider special to perfect in high-grade oscillograph. Have on oscillograph at present: Defer sparks, spark orderly, burr sparks, interval sparks, leakage breaks logistic face to spark, TV sparks, this sparking...
5, analytic function: Should have very strong automatic processing, operation, test and the capacity that analyse the signal that be measured.
1) form and failure of parameter qualification ／ are sentenced automatically try a function;
2) advanced function processing: Average, differential, extremely sth resembling a net of cent, index, logarithm, power, evolution, bag, high component is made wait for operation function;
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