3456A操作说明书手册sManualPart2of2

Mudel 3456AOperationTable 3-4.Optimizing Reading Rate (Cont'd).as you could.Why?Because you have not optimally handl-store measurement sequences in its memory,and tiag theed the transfer of data over the bus from the 3456A tocomputer when it is done,lets you use both the 3456A andyour computer.the computer to their best advantage.To avoid overrunningthe computer with data from the 3456A,you can selectI at's take a closer look at the reasons for fast reading rates:the Svstems Output mode which updates the output onlyafter handshake.High speed scanningData ThroughputWAVEFORM CHARACTERIZATIONWaveform CharacterizationThe 3456A can digitize sinewaves up to about 100 HzHIGH SPEED SCANNINGwith fairly good accuracy.All the high speed modes mustbe used to acquire at least two samples per cycle.TheTypical applications of high speed scanning includeDelay generator gives you about 1%timing accuracy.temperature and strain profiling where a large number ofmeasurements must be taken very quickly to "'treeze"theWaveform characterization should be performed with aphenomenon at some point in time.For this type measure.System Voltmeter.These voltmeters use a sample and holdtechnique which allows the waveform to be "'frozen''at ament,data transfer from the voltmeter to the computer isnot really required to go fast.As long as the scanner datawell-defined point in time.An integrating-type voltmeter,does not exceed 350 measurements,the built-in memorylike the 3456A,will always average the waveform over itscan store all the measurements for one scanned sequenceintogretion poriod giving looo ooouroto rooulto,Syotomvoltmeters also typically have higher speed,greater band-and transfer the data at the end of acquisition.In conjunc.tion with Reading Storage,three other 3456A featureswidth,and much more precise delay generationmake high speed scanning particularily easy to do:To summarize,let's look at the fastest reading rate set up·Program Memoryeliminated and that the data is stored internally in the pack-·Voltmeter Completeed mode.This may not be right for your use.You may wantExternal Triggera final answer which the Math functions could providewithout computer interaction.Program Memory can be used to store a serles of measure-ment sequences and operate on the acquired data.For ex-ample,in a high speed scanning situation you could acquirethe measurements as fast as possible in the Reading Store8mode.Flag the computer and then output the data,perhapsalready scaled.in ASCll format.It is almost a 10 to 1 sav-ings in time during acquisition and the results are just aseasy to use as if you load,acquire,and transfer individualreadings.Voltmeter Complete can be used to increment thescanner sequentiallv without software interaction betweenthe voltmeter,the scanner,and the computer.To close the loop,the scanner can output a signal to the603456A's internal trigger.The result is that once themoasuroments aro initiated by your computethere is noadditional need for computer interacti