two channels delay time measurment

[还是秘密]

I have a Agilent 6032a Scope and am trying to learn how to use it to make measurements in LabView 7.1. I have been able to make single channel scalar measurements, such as frequency, RMS voltage, etc. However, I now need to write code that takes a delay time measurement between the two channels.
I cannot figure out how to get started, and I cannot find any examples of a measurement like this.

There is a picture about i want to measurment.

[Russ_Evans]

The first thing you need to do is to read the waveforms. You should be able to find LV drivers for this scope on the instrument driver network at

http://www.ni.com/devzone/idnet/default.htm

Once you can read the waveforms for selected channels then you can do the analysis of the time delay. If the waves look exactly like your image you could search the array for a zero crossing (or whatever lower limit works), then compare the time of these crossings. Another method (again if the waves are as you pictured) is to look for the corresponding time (xaxis value) associated with ymin value (or ymax as the case dictates) for the arrays (waveforms). Now all this can be done either as arrays or as LV waveforms I am not sure what the agilent instrument driver uses or which you are more comfortable using.

hope this helps

Cheers,

--Russ

[HSD]

A little late I know ...

Other options:

1.  NI-Scope measurment library has a built in two channel time delay measurement.  This will work if you are using a NI digitizer.

2.  If you are measuring the difference between two repeative waveforms then phase delay is the most accurate method.  This is where you calucated the phase of each waveform and divide by 360 degrees and multiply by the frequency of the waveform.  The difference of time between the two channels is your skew.  Note that the accuracy of this measurement is limited by the resolution of your device.  Ex. a 14bit 100 MS/s measurement device will give you far better measurements than a 2 GS/s 8bit device.