signal generation and analysis

[temporalnexus]

I was wondering if there exists a VI that allows me to:
1) Acquire previously logged data along with it's timeing (a 2D log file with data in 1 and timeing in other).  The data is in fact a function (waveform).
2) Display the previously logged data as a waveform on the screen.  Then mark the timeing period of the data.  So basically take a continous data and sample it at specific time (digitize it) then send just the sampled data.  But I also need to see (overlay on top of my waveform) which parts of the waveform are being sampled and thus sent.
3) In addition overlay or create another waveform display but this time showing just the digitzied data, that way I can see what the sampled output looks like (a discreate data "chopy" set and not a continous waveform).  Also I would like to be able to modify the sampling timeing of the specific points of the waveform before the sampled data points are sent. i.e. Be able to shift the sampling timeing, add additional sample without changieng the overall sample timeing, shift the initial timeing period (instead of t=0 of the waveform I want this to start sampling at t=3s into the waveform). 
etc.

So basically is there a VI that does that and if so then where is it?

P.S.
Also it would be nice if the VI could in addition acquire the data from the live signal (via GPIB or DAQ).  Therefore it would be a 2 part capability, 1 being an allready loged data digitization and sending and 2 live data digitization and sending.

Thank you

[Dennis_Knutson]

There doesn't exist a single VI but if I understand you correctly, it should all be doable.

You can read a saved file with a couple of different methods. One way is the Read From Spreadsheet, Another is Read Waveform From File. There are other possibilities and it all depends on exactly how the original waveform was saved and what program did the saving. Describe in greater detail exactly what's in the file or post an example.

Once you've read a waveform, it's simply a matter of using a graph to display it. If you create a waveform datatype from the file, then that includes the timing information. Since the original data on disk is not continuous, but already sampled, I'm not sure what you mean. There is a function called Resample Waveform on the Analyze>Waveform Conditioning palette. You specify a new t0, dt, and interpolation. Showing a continuous or non-continuous waveform on a graph is simply a matter of selecting the interpolation. You can right click on the plot legend for the specific plot and select the style.

Data acquisition from a DAQ board or GPIB device is a common task. For DAQ, I would recomend that you look at the shipping examples. Open Help>Find Examples and from the browse tab, expand the Hardware Input and Output>DAQmx>Analog Measurements to get you started.