The optical data signals and the noise vectors are defined in a list, which can contain more than one signal. If an optical signal `E`

is defined as done in the basic setup above, the optical signal itself is represented by two numpay arrays which contains the complex
sample values of the X- and the Y-polarisation plane. `E[0]['E'][0]`

is the X-polarisation and `E[0]['E'][1]`

is the Y-polarisation:

```
>>> E[0]['E']
array([[ 4.42838749e-003 -6.11669972e-004j,
4.44132200e-003 -4.55343696e-004j, ...,
4.40185784e-003 -7.45482750e-004j,
4.41682653e-003 -6.81389659e-004j],
[ -4.94065646e-003 +0.00000000e+000j,
-4.94065646e-003 +0.00000000e+000j, ...,
-4.94065646e-003 +0.00000000e+000j,
-4.94065646e-003 +0.00000000e+000j]])
```

Each array contains $SPS * NOS$ samples. The unit is $\sqrt{W}$.

Noise is represented as a noise vector in the frequency domain. The number of noise bins is $SPS * NOS$. The bins have a frequency resolution of $f_S / SPS$ and the unit is $W/Hz$.

```
array([ 6.15149232e-11, 6.15149232e-11, 6.15149232e-11, ...,
6.15149232e-11, 6.15149232e-11, 6.15149232e-11])
```