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08-01-2016 09:31 AM
Hi there,
I am new to LabVIEW.
I just want to generate a wave whose frequency is higher than fs/2 using the signal Generation VI and take 10 samples.
When I raised the frequency above 500Hz, the Generator on the top refused to work, giving me an erro.
Could anyone give me a hand?
Thanks in advance.
08-01-2016 09:35 AM
@Dirichlet123 wrote:
[...]whose frequency is higher than fs/2 [...]
Ever heared of Nyquist theorem? If not, read about it. It explains the background and is a physical constraint.
Be glad that the waveform generation VI prevents you from trying by throwing an error.
Norbert
08-01-2016 09:40 AM
Uhm... I did know that. I intended to violate the Nyquist theorem to see the aliasing.
I just want to take 10 discrete samples from the underlying signal. Thanks anyway!
08-01-2016 09:43 AM
To see aliasing, you have to "acquire" a signal. What you can do:
Create a signal with higher frequency and the use "resampling" breaking Nyquist.
Norbert
08-01-2016 10:13 AM
Thanks, it works. But is there a way to generate an array consisting 10 samples regardless of what sampling frequency I use?
Say I have a analog signal y=sin(2*pi*f0*t) ,I take 10 samples using the sampling frequency fs, so the outputs are y[k]=sin(2*pi*f0*k/fs).