Plot a scatter plot or a theorical constellation diagram

Calling sequence

plot_const(x)        // Scatter plot view
plot_const(x,'i')    // Scatter plot view, force identic x and y scale
plot_const(wf)       // Waveform constellation plot



I/Q signal (I is real part, Q is imaginary part) to plot


waveform object (as can be initialized by wf_init)


Plot .

Example 1: plotting a theorical constellation

wf = wf_init('qpsk');
clf(); plot_const(wf);

Example 2: Scatter plot

// Generate a test 8PSK signal, with:
// sampling frequency = 1 MHz, zero IF, symbol frequency = 100 kHz
fs = 1e6; fi = 0; fsymb = 100e3;
mod = mod_init('8psk',fs,fi,fsymb);
b = prbs(1000); // Random bit sequence
[mod,x] = mod_process(mod,b);
x = awgn(x,0.02); // Add some noise
clf(); plot_const(x, 'i');


Cannot be used in the same figure as other plots (except other plot_const), because of an incompatibility due to the colormap function.