kaira.modulations.Pi4QPSKModulator

Inheritance diagram for Pi4QPSKModulator

class kaira.modulations.Pi4QPSKModulator(gray_coded: bool = True, *args, **kwargs)

Bases: BaseModulator

Π/4-QPSK (π/4 shifted QPSK) modulator.

A variant of QPSK where the constellation is rotated by π/4 radians on alternating symbols, providing improved envelope properties.

Methods

__init__	Initialize the π/4-QPSK modulator.
forward	Modulate bit pairs to π/4-QPSK symbols or symbols to π/4-QPSK signals.
plot_constellation	Plot the π/4-QPSK constellation diagram.
reset_state	Reset internal state (constellation alternation).

Attributes

bits_per_symbol	Number of bits per symbol.
qpsk
qpsk_rotated
constellation
bit_patterns

qpsk: Tensor

qpsk_rotated: Tensor

constellation: Tensor

bit_patterns: Tensor

__init__(gray_coded: bool = True, *args, **kwargs) → None

Initialize the π/4-QPSK modulator.

Parameters:

• gray_coded – Whether to use Gray coding for mapping (default: True)

• *args – Variable length argument list.

• **kwargs – Arbitrary keyword arguments.

forward(x: Tensor, *args, **kwargs) → Tensor

Modulate bit pairs to π/4-QPSK symbols or symbols to π/4-QPSK signals.

Parameters:

• x – Input tensor of bits with shape (…, 2*N) or symbols with shape (N,)

• *args – Variable length argument list.

• **kwargs – Arbitrary keyword arguments.

Returns:

Complex tensor of π/4-QPSK symbols with shape (…, N)

reset_state() → None

Reset internal state (constellation alternation).

plot_constellation(**kwargs) → Tuple[Figure, Axes]

Plot the π/4-QPSK constellation diagram.

Parameters:

**kwargs – Additional arguments passed to plot_constellation

Returns:

Matplotlib figure object

property bits_per_symbol: int

Number of bits per symbol.