CWgraph - how to set db in Y-Axes

[Rafi2003]

Hi,

I would like to use the CWGraph component to display the frequency domain of a signal.    Please see the attached photo for the desired result.

I couldn't find how to set the Y-axes to db scale.

Please help

Thanks

Rafi

[Eric_B.]

Rafi,

Are you looking to change the label of the Y-axis or actually do a transform on your signal to get the frequency domain?  The FFT function in Visual Basic is only available in the Measurement Studio Enterprise edition (http://www.ni.com/analysis/cwtools_analysis.htm), but as long as you have that, you can apply an FFT and then plot the new function.

[Rafi2003]

Hi Eric and thanks for your response

1. I am looking to do the frequency response

2. I do have the enterprise edition which also include LabView and CVI

3. I'm working on a project which is written in VB6 and that is why I prefer to use the measurement studio to perform the signal analysis.  I know that I can do the analysis in LabView and call it from VB.  I will check that option only if I won't be able to accomplish the task with the measurement studio.  What do you think?  (see the list of task I need to deal with)

4. My project requires reading data (could be hundreds thousands of points) and then, displaying:  
            Time domain
            frequency domain
            frequency response 
            histogram
            Pulse response
    Also calculating:
            SNR
            Linearity
            rms
            p-p

Any advice would be greatly appreciated

Rafi

[Eric_B.]

Rafi,

The Enterprise edition does include that extra software, but it also indicates that you have more functionality in Measurement Studio.  Therefore, anything in the Enterprise column under VB 6.0 ActiveX Controls, you can do solely in Visual Basic.

All of the Visual Basic Analysis examples should be installed here: C:\Documents and Settings\All Users\Documents\National Instruments\MStudioVS6\VB\Samples\Analysis .  This is a good place to start for using the analysis libraries.  Specifically, it has examples on histograms, filtering and some statistics functions, among other things.  The help (Start Menu»Programs»National Instruments»Measurement Studio for Visual Studio 6»Help»Measurement Studio Reference has a function reference so you can see how to call all of the Analysis functions.