optic.comm.modulation.apskConst

apskConst(M, m1=None, phaseOffset=None)[source]

Generate an Amplitude-Phase Shift Keying (APSK) constellation.

Parameters:

M (int) – Constellation order.
m1 (int) – Number of bits used to index the radii of the constellation.
phaseOffset (float, optional) – Phase offset applied to each ring of the constellation [rad]. The default is pi / symbolsPerRing.

Returns:

const – APSK constellation

Return type:

np.array

Notes

symbols per ring is determined by \(m_2 = log_2(M) - m_1\), where \(m_1\) is the number of bits used to index the rings. If \(m_1\) is not provided, it is set based on M according to references [1] and [2].

References

[1] Z. Liu, et al “APSK Constellation with Gray Mapping,” IEEE Communications Letters, vol. 15, no. 12, pp. 1271-1273, 2011.

[2] Proakis, J. G., & Salehi, M. Digital Communications (5th Edition). McGraw-Hill Education, 2008.