real time 3D plot of spectrum

[tintin99]

Hi

Would you please show me with a basic example how can I plot a 3D graph ( time-frequency- amplitude or time-frequency-power) in real time? I can use the modulation toolikit blocks to plot amplitide vs f or power vs f but I don't know how can I add time as the third axis . Considet the IQ sampling rate is 200k and the carrier frequency is 2.4 GHz

Many thanks

[X. · Accepted solution]

Not sure what kind of performance you are expecting (and you can achieve) but if you get a series of A(f) plots that you want, say, to represent as a waterfall type of 3D graph, the 3D waterfall graph example should be a good starting point (accessible through the detailed help).

You have two options in it: either pass the whole data set as three 2D arrays or two 1D arrays and one 2D array. Here is an illustration with the latter approach:

My dual core PC is completely overloaded by the 3D display task and rapidly fills up its memory...

HTH.

[tintin99]

Many thanks . The ramp function was my problem.

Just few questions

1- How can I take measurments every n seconds. Do I need to just change the input value of Wait function to n*1000 or it is better to yse a timed loop

2- Also how can I export the value of X,y,Z to excel

3- And finally I have the same problem for 3D display. Is there any solution for it?

[X.]

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@tintin99 wrote:

Many thanks . The ramp function was my problem.

Just few questions

1- How can I take measurments every n seconds. Do I need to just change the input value of Wait function to n*1000 or it is better to yse a timed loop

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 Changing the wait function argument should do the trick. Timed loop are really meaningful only with realtime systems (FPGA, RT OS).

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2- Also how can I export the value of X,y,Z to excel

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You could export to a tabulated ASCII file using File>> Write to Spreadsheet File VI.

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3- And finally I have the same problem for 3D display. Is there any solution for it?

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You could NOT use a 3D display and limit yourself to displaying those curves on a Graph, for one. Or if you absolutely want to use this representation, only display the last 30 or whatever number is convenient for you (as illustrated on the attached example).