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komm.ASKModulation

Amplitude-shift keying (ASK) modulation. It is a complex modulation scheme in which the points of the constellation symbols are uniformly arranged in a ray. More precisely, the $i$-th constellation symbol is given by $$ x_i = iA \exp(\mathrm{j}\phi), \quad i \in [0 : M), $$ where $M$ is the order (a power of $2$), $A$ is the base amplitude, and $\phi$ is the phase offset of the modulation. The ASK constellation is depicted below for $M = 4$.

4-ASK constellation.

__init__

Constructor for the class.

Parameters:

  • order (int) –

    The order $M$ of the modulation. It must be a power of $2$.

  • base_amplitude (Optional[float]) –

    The base amplitude $A$ of the constellation. The default value is 1.0.

  • phase_offset (Optional[float]) –

    The phase offset $\phi$ of the constellation. The default value is 0.0.

  • labeling (Optional[Array1D[int] | str]) –

    The binary labeling of the modulation. Can be specified either as a 2D-array of integers (see base class for details), or as a string. In the latter case, the string must be either 'natural' or 'reflected'. The default value is 'reflected', corresponding to the Gray labeling.

Examples:

The ASK modulation with order $M = 4$, base amplitude $A = 1$, and Gray labeling is depicted below.

4-ASK modulation with Gray labeling.

>>> ask = komm.ASKModulation(4)
>>> ask.constellation
array([0.+0.j, 1.+0.j, 2.+0.j, 3.+0.j])
>>> ask.labeling
array([[0, 0],
       [1, 0],
       [1, 1],
       [0, 1]])
>>> ask.modulate([0, 0, 1, 1, 0, 0, 1, 0, 1, 0])
array([0.+0.j, 2.+0.j, 0.+0.j, 1.+0.j, 1.+0.j])