mokka.utils

Utilities sub-module for MOKKa.

This sub-module contains a lot of useful utiltiies used throughout the MOKKa package.

mokka.utils.N0(SNR)

Calculate \(N_0\) from SNR.

Parameters:

SNR – signal-to-noise ratio \(s\) [dB]

Returns:

\(10^{-\frac{s}{10}}\)

mokka.utils.beta2(D, wavelength)

Calculate \(\beta_2\) from the dispersion coefficient and wavelength.

Parameters:

  • D – Dispersion coefficient [ps/nm/km]

  • wavelength – wavelength of optical carrier [nm]

Returns:

beta2 in [ps**2/km]

mokka.utils.bits2hex(bits)

Convert bit array to their hex representation MSB first.

Parameters:

bits – array of bit arrays

Returns:

list of hex strings

mokka.utils.bits2int(bits)

Convert bit array to their integer representation MSB first.

Parameters:

bits – array of bit arrays

Returns:

array of ints

mokka.utils.db2pow(ydb)

Calculate the power in linear units.

Parameters:

ydb – power in decibel [dB]

Returns:

power in linear units [W]

mokka.utils.dbm2pow(ydbm)

Calculate the power in linear units.

Parameters:

ydbm – power in dBm [dBm]

Returns:

power in linear units [W]

mokka.utils.estimate_SNR(x, y)

Calculate the (non-linear) SNR from the sent and received symbols.

Params x:

signal vector

Params y:

signal + noise vector

mokka.utils.export_constellation(output_file, constellation)

Export a constellation to a csv file.

Parameters:

  • output_file – path to file

  • constellation – tensor of complex constellation points

Returns:

mokka.utils.hex2bits(hexs, m)

Convert list of hex strings to their bit representation MSB first.

Parameters:

  • hexs – list of hex strings

  • m – bit-width per hex

Returns:

array of bit arrays

mokka.utils.ints2bits(ints, m)

Convert integers to their bit representations MSB first.

Parameters:

  • ints – array of ints

  • m – bit-width per int

Returns:

array of bit arrays

mokka.utils.plot_bitwise_decision_regions(axs, demapper, num_samples=10000, meshgrid=False, additional_args=None, sample_radius=1.2)

Plot the bitwise decision regions of the demapper.

This is done by either sampling random points within a radius or using a meshgrid to sample points along the real and imaginary axis with a fixed spacing.

Parameters:

  • axs – Matplotlib axis

  • demapper – demapper object

  • num_samples – number of samples in total or per axis is meshgrid is used

  • meshgrid – Use a meshgrid to sample the 2D area

  • additional_args – additional arguments to provide to the demapper

  • sample_radius – either the radius or the maximum amplitude for meshgrid

mokka.utils.plot_classifier(ax, class_fn, range_x, range_y, points_x, points_y)

Plot classifier regions.

Params ax:

matplotlib axis

mokka.utils.plot_constellation(ax, constellation, label=True, keep=False, color=None, size=2, probabilities=None, label_type='hex')

Plot constellation points.

Parameters:

  • ax – matplotlib axis

  • constellation – Constellation points in the order of their bitlabels

  • label – Switch to plot labels

  • keep – Keep existing drawing on the axis

  • color – Color for the constellation points

  • size – Size of the constellation points

  • probabilities – scale the size of the constellation according to their probability.

  • label_type – Hexadecimal or bitstring labels

Returns:

axis

mokka.utils.plot_scatter(ax, samples, labels)

Scatter plot a bunch of samples with labels.

Params ax:

matplotlib axis

Params samples:

complex samples to plot

Params labels:

list of labels assigning a label per sample

mokka.utils.pow2db(y)

Calculate the power in decibel.

Parameters:

y – power in linear units [W]

Returns:

power in decibel [dBW]

mokka.utils.pow2dbm(y)

Calculate the power in dBm.

Parameters:

y – power in linear units [W]

Returns:

power in dBm [dBm]

mokka.utils.setup_logging(level, component='')

Configure the Python logging module to print logs for given component and minimum level on stdout.

Parameters:

  • level – A level from the logging module as minimum level

  • component – The parent component for which all logs should be displayed.

mokka.utils.setup_plot(title)

Create a figure and axes.

Params title:

Title of the figure

mokka.utils.sigma_phi(linewidth, symbolrate)

Calculate \(\sigma_{\phi}\) given a laser linewidth and symbol rate.

Parameters:

  • linewidth – laser linewidth \(\Delta f\) [Hz]

  • symbolrate – symbol rate \(R_{\mathrm{sym}}\) [Bd]

Returns:

\(\sqrt{2 \pi \Delta f / R_{\mathrm{sym}}}\)

mokka.utils.wavelength(D, beta2)

Calculate the wavelength from \(\beta_2\) and the dispersion coefficient.

Parameters:

  • D – Dispersion coefficient [ps/nm/km]

  • beta2 – Group velocity dispersion [ps**2/km]

Param:

returns wavelength of optical carrier [nm]

This sub-module provides decorators for use in mokka.

mokka.utils.decorators.deprecated(reason)

Mark functions as deprecated.

It will result in a warning being emitted when the function is used.

Parameters:

reason – Human readable reason for deprecation of function or class