How to sample a random signal generated by random generator?

[Anonymous]

I am new to LabVIEW. Please provide me better solution.

[Anonymous]

Hello Project Support,

Thank you for contacting National Instruments.

A basic data acquisition system consists of a signal (usually from a
transducer), signal conditioning, a DAQ device, and driver level /
application level software.

What data acquisition system are you currently using? If you can
provide a little more information, I will be happy to help you put
together data acquisition code in LabVIEW. The following information
would be helpful:

1) Type of DAQ card (if any)
2) Version of NI-DAQ (driver)
3) Version of LabVIEW
4) Operating System
5) The characteristics of the signal you are acquiring

Regards,

Matthew C
Applications Engineer
National Instruments

[Anonymous]

Sir,

First of all I want to thank you for answering. Actually I am not
using any DAQ card. I am using simple random signal generator from the
Tool palette. In the graph i am getting the amplitude values only time
values of 0,1,2,.. instances and i need the help to get the values
between these ranges (i.e. between 1 and 2 I need the amplitude of the
signal). How can i get these intermediate points. Here actually i am
fixing a threshold. I want the time value at which the curve crosses
the threshold.

Kindly help me in this regard.

Ramkumar. D
Project Support,
Soliton Automation India Private Ltd,
India.

[Anonymous]

Sir,

I am attaching the VI from which you can understand my actual problem.
Here i want to extract the Time values at which the curve crosses the
threshold. How to get this.

Kindly help me in this regard.

Ramkumar. D
Project Support,
Soliton Automation India Private Ltd.

[Matthew C]

Hello,

I apologize for the delayed response.

I took a look at your VI. In its current state, you will not be able to extract Y values for X values in-between those that you plotted. The XY graph is simply connecting your points to provide a visual representation. No real data exists between the points that you plotted.

What you will need to do is first use one of LabVIEW's built-in curve fitting functions to fit a curve to your randomized data. These functions are located on the Analyze >> Mathematics >> Curve Fitting palette.

Once you fit a curve to your data, you will be able to trace the curve with your cursor. You can observe the XY-values that the cursor passes over by displaying the cursor legend. Right click the XY-graph and select Visible
Items >> Cursor Legend.

You may also want to consider using LabVIEW's mathematics functions to evaluate the x-values you are interested in. One solution would be to vertically shift your best-fit curve by the threshold value and evaluate the zeros of the curve using LabVIEW's built-in functions. These functions can be found on the Analyze >> Mathematics >> Zeros palette.

I hope this helps! If you have further questions, let me know.

Matthew C
Applications Engineer
National Instruments