FFT of Linear FM Pulse Waveform

After I generate a waveform using phased.LinearFMWaveform from the Phased Array System Toolbox, how do I take the FFT of this waveform?

prf = [1e3];
waveform = phased.LinearFMWaveform('PRF',prf,'SweepBandwidth',200e3,'PulseWidth',100e-6,'NumPulses',5);
sig = waveform();
T = length(sig)*(1/waveform.SampleRate);
t = unigrid(0,1/waveform.SampleRate,T,'[)');
plot(t,real(sig))
xlabel('millisec')

When I try to take fft(waveform), MATLAB shows the error:

Error using fft
Invalid data type. First argument must be double, single, int8, uint8, int16, uint16, int32, uint32, or
logical.

Answer 1

[Hrishikesh Borate]

Hi,

It’s my understanding that you are trying to generate FFT of waveform, which you have generated using phase.LinearFMWaveform from Phased Array System Toolbox. The fft function doesn’t support waveform object as it’s argument. So, the solution would be to pass sig as argument instead of waveform. Use fft(sig) in your code.

For more information, refer to FFT Documentation