MATLAB: How to generate complex envelop signal using chirp function

complex envelop chirp signalPhased Array System ToolboxRF ToolboxSignal Processing Toolbox

Matlab chirp function will generate cosine-based chirp signal, say from f1 to f2 with 10MHz linear chirp. How to modulate the signal to a carrier at fc, and in complex envelop form?

Best Answer

One way to get the complex chirp is to form analytical signal, e.g.,
f1 = 0; f2 = 10;
t = 0:0.01:1;
xi = chirp(t,f1,1,f2);
x = hilbert(xi);
Alternatively, you can just use a complex chirp signal equation to derive it, like
x1 = exp(1i*pi*(f2-f1)*t.^2);
To modulate to the carrier, you need to multiply the carrier signal, like
fc = 50;
xm = x.*exp(1i*2*pi*fc*t);
However, most simulation is done in complex baseband and even in RF simulation it models the effect of RF distortion on the baseband signal.
HTH
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