sdr.plot.constellation(x_hat: NDArray[complex_], heatmap: bool = False, limits: tuple[float, float] | None = None, **kwargs)

Plots the constellation of the complex symbols \(\hat{x}[k]\).

Parameters:
x_hat: NDArray[complex_]

The complex symbols \(\hat{x}[k]\).

heatmap: bool = False

If True, a heatmap is plotted instead of a scatter plot.

limits: tuple[float, float] | None = None

The axis limits, which apply to both the x- and y-axis. If None, the axis limits are set to 10% larger than the maximum value.

**kwargs

If heatmap=False, additional keyword arguments to pass to matplotlib.pyplot.scatter(). The following keyword arguments are set by default. The defaults may be overwritten.

  • "range": +/- 10% of the maximum value

  • "bins": 75, which is the number of bins per axis

If heatmap=True, additional keyword arguments to pass to matplotlib.pyplot.hist2d(). The following keyword arguments are set by default. The defaults may be overwritten.

  • "marker": "."

  • "linestyle": "none"

Example

Display the symbol constellation for Gray-coded QPSK at 6 dB \(E_s/N_0\).

In [1]: qpsk = sdr.PSK(4, phase_offset=45); \
   ...: s = np.random.randint(0, qpsk.order, 10_000); \
   ...: x = qpsk.map_symbols(s); \
   ...: x_hat = sdr.awgn(x, 6);
   ...: 

In [2]: plt.figure(figsize=(8, 4)); \
   ...: sdr.plot.constellation(x_hat);
   ...:
../../_images/sdr_plot_constellation_1.png

Display the symbol constellation using a heatmap.

In [3]: plt.figure(figsize=(8, 4)); \
   ...: sdr.plot.constellation(x_hat, heatmap=True);
   ...:
../../_images/sdr_plot_constellation_2.png