plotting the power spectrum density

Hello; i want to plot the PSD (dBm/Hz) against the frequency (MHz) i only have the IQ data as vector and the sampling frequency.

please help me to plot it in the right way using Matlab code.

Thank you.

Answer 1

[dpb]

There's a good example at

doc fft

[mohammed ali]

what do you mean by doc? do u mean documents?

[dpb]

Type it and see...

[mohammed ali]

i couldn't find anything useful for me. i need to plot a carrier from power amplifier that have IQ data as input and output and i need to plot the PDS for the both, can i know in which frequency this carrier lie in?

[dpb]

How do I (or are any of us here, for that matter are to) know what frequency your data are? That's entirely up to the data generation/collection process.

BUT if you do know the sampling frequency (and, pretty much, you've got to get anywhere), then the example pointed to previously shows how the frequency spectrum is related; presuming the data you have are somehow generated analogously to performing an FFT on a time-sampled signal. I have no klew what an "IQ data" vector would be, sorry...