pychopmarg.com

Classes

class pychopmarg.com.COM(com_params: COMParams, channels: Path | dict[str, list[Path]], vic_chnl_ix: int = 1, debug: bool = False, do_init: bool = True)[source]

Encoding of the IEEE 802.3-22 Annex 93A/178A ‘Channel Operating Margin’ (COM) specification.

status_str = 'Ready'
opt_mode = 2
norm_mode = 1
unit_amp = True
tx_ix: int = 0
rx_taps: ndarray[Any, dtype[Real]] = array([1.])
dfe_taps: ndarray[Any, dtype[Real]] = array([], dtype=float64)
gDC = 0.0
gDC2 = 0.0
vic_chnl_ix = 1
cursor_ix: int = 0
zp_sel = 0
com_params = COMParams(fb=106.25, fstep=0.01, fmax=40000000000.0, L=4, M=32, DER_0=0.0002, T_r=0.004, RLM=0.95, A_v=0.413, A_fe=0.413, A_ne=0.45, R_0=50, A_DD=0.02, SNR_TX=33, eta_0=6e-09, sigma_Rj=0.01, f_z=42.5, f_p1=42.5, f_p2=106.25, f_LF=1.328125, g_DC=[0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11, -12, -13, -14, -15], g_DC2=[0.0, -0.5, -1.0, -1.5, -2.0, -2.5, -3.0, -3.5, -4.0, -4.5, -5.0], tx_taps_min=[-0.06, 0.0, -0.34, -0.2, 0.0, 0.0], tx_taps_max=[0.0, 0.12, 0.0, 0.0, 0.0, 0.0], tx_taps_step=[0.005, 0.005, 0.005, 0.005, 0.0, 0.0], c0_min=0.5, f_r=0.58, dfe_min=array([0.]), dfe_max=array([0.85]), rx_taps_min=array([-0.7, -0.7, -0.7, -0.7, -0.7,  1. , -0.7, -0.7, -0.7, -0.7, -0.7,        -0.7, -0.7, -0.7, -0.7, -0.7]), rx_taps_max=array([0.7, 0.7, 0.7, 0.7, 0.7, 1. , 0.7, 0.7, 0.7, 0.7, 0.7, 0.7, 0.7,        0.7, 0.7, 0.7]), dw=5, R_d=array([50.]), C_d=[4e-05, 9e-05, 0.00011], C_b=[3e-05], C_p=[4e-05], L_s=[0.13, 0.15, 0.14], z_c=[87.5, 92.5], z_p=[33, 1.8], gamma0=0.0005, a1=0.00089, a2=0.0002, tau=0.006141, z_pB=1.8)
debug = False
chnls: list[tuple[tuple[Network, str], ndarray[Any, dtype[Comp]]]] = []
chnls_noPkg: list[tuple[tuple[Network, str], ndarray[Any, dtype[Comp]]]] = []
pulse_resps_nopkg: list[ndarray[Any, dtype[Real]]] = []
pulse_resps_noeq: list[ndarray[Any, dtype[Real]]] = []
nRxTaps: int = 0
nRxPreTaps: int = 0
rx_ffe_phase_matrix: ndarray[Any, dtype[Comp]] = array([], dtype=float64)
property fb: float

Baud. rate (Hz)

property ui: float

Unit interval (s)

property nspui: int

Samples per UI

property times: ndarray[Any, dtype[Real]]

System time vector (s); decoupled from system frequency vector!

property fstep: float

Frequency step (Hz)

property fmax: float

Maximum frequency (Hz)

property freqs: ndarray[Any, dtype[Real]]

System frequency vector (Hz); decoupled from system time vector!

property Xsinc: ndarray[Any, dtype[Real]]

Frequency domain sinc(f) corresponding to Rect(ui) in time domain.

property Ht: ndarray[Any, dtype[Comp]]

Return the voltage transfer function, H(f), associated w/ the Tx risetime, according to (93A-46).

property num_tx_combs: int

Return the number of available Tx FFE tap weight combinations.

property Hr: ndarray[Any, dtype[Comp]]

Return the voltage transfer function, H(f), of the Rx AFE, according to (93A-20).

property Hctf: ndarray[Any, dtype[Comp]]

Return the voltage transfer function, H(f), of the Rx CTLE, according to (93A-22).

calc_Hctf(gDC: float | None = None, gDC2: float | None = None) → ndarray[Any, dtype[Comp]][source]

Return the voltage transfer function, H(f), of the Rx CTLE, according to (93A-22).

Keyword Arguments:

  • gDC – CTLE first stage d.c. gain (dB). Default: None

  • gDC2 – CTLE second stage d.c. gain (dB). Default: None

Notes

1. The instance’s current value(s) for gDC and gDC2 are used if not provided. (Necessary, to accommodate sweeping when optimizing EQ.)

property gamma1_Tx: float

Reflection coefficient looking out of the left end of the channel.

property gamma2_Tx: float

Reflection coefficient looking out of the right end of the channel.

property gamma1_Rx: float

Reflection coefficient looking out of the left end of the channel.

property gamma2_Rx: float

Reflection coefficient looking out of the right end of the channel.

sDie(isRx: bool) → Network[source]

On-die parasitic capacitance/inductance ladder network, including bump.

property sPkgRx: Network

Rx package response.

property sPkgTx: Network

Tx package response.

property sPkgNEXT: Network

NEXT package response.

add_pkg(ntwk: tuple[Network, str]) → tuple[tuple[Network, str], ndarray[Any, dtype[Comp]]][source]

Add package response to raw channel and pre-calculate H21.

set_status(status: str) → None[source]

Set the GUI status string and print it if we’re debugging.

sC(c: float) → Network[source]

Return the 2-port network corresponding to a shunt capacitance, according to (93A-8).

Parameters:

c – Value of shunt capacitance (F).

Returns:

2-port network equivalent to shunt capacitance, calculated at given frequencies.

Htx(tx_taps_ix: int) → ndarray[Any, dtype[Comp]][source]

Return the complex frequency response of the Tx deemphasis filter.

Parameters:

tx_taps_ix – Index into the Tx tap weight combinations list.

Returns:

Complex frequency response of Tx deemphasis filter.

Hffe_Rx(taps: ndarray[Any, dtype[Real]] | None = None) → ndarray[Any, dtype[Comp]][source]

Return the complex frequency response of the Rx FFE.

Keyword Arguments:

taps – Tap weights to use for calculation. Default: None (Means “use self.rx_taps”.)

Returns:

Complex frequency response of Rx FFE.

Raises:

ValueError – If taps is supplied and the length is wrong.

H(H21: ndarray[Any, dtype[Comp]], tx_ix: int, Hctf: ndarray[Any, dtype[Comp]] | None = None, rx_taps: ndarray[Any, dtype[Real]] | None = None, dfe_taps: ndarray[Any, dtype[Real]] | None = None, passive_RxFFE: bool = False) → ndarray[Any, dtype[Comp]][source]

Return the voltage transfer function, H(f), of a complete COM signal path, according to (93A-19).

Parameters:

  • H21 – Voltage transfer function of channel + package.

  • tx_ix – Tx FFE tap weights index.

Keyword Arguments:

  • Hctf – Complex voltage transfer function of CTLE. Default: None (i.e. - Calculate, using self.gDC & self.gDC2.)

  • rx_taps – Rx FFE tap weights. Default: None (i.e. - Use self.rx_taps.)

  • dfe_taps – Rx DFE tap weights. Default: None (i.e. - Use self.dfe_taps.)

  • passive_RxFFE – Enforce passivity of Rx FFE when True. Default: True

Returns:

Complex voltage transfer function of complete path.

Raises:

  • ValueError – If the length of the given voltage transfer function

  • differs from the length of the system frequency vector. –

Notes

  1. It is in this processing step that linear EQ is first applied.

2. Any unprovided EQ values are taken from the COM instance. If you really want to omit a particular EQ component then call with:

  • tx_taps: []

  • rx_taps: [1.0]

  • Hctle: ones(len(self.freqs))

pulse_resp(H: ndarray[Any, dtype[Comp]]) → ndarray[Any, dtype[Real]][source]

Return the unit pulse response, p(t), corresponding to the given voltage transfer function, H(f), according to (93A-24).

Parameters:

H – The voltage transfer function, H(f). Note: Possitive frequency components only, including fN.

Returns:

The pulse response corresponding to the given voltage transfer function.

Raises:

ValueError – If the length of the given voltage transfer function differs from that of the system frequency vector.

Notes

  1. The pulse response is trimmed to match the length of the system time vector.

gen_pulse_resps(chnls: list[tuple[tuple[Network, str], ndarray[Any, dtype[Comp]]]] | None = None, Hctf: ndarray[Any, dtype[Comp]] | None = None, tx_ix: int | None = None, rx_taps: ndarray[Any, dtype[Real]] | None = None, dfe_taps: ndarray[Any, dtype[Real]] | None = None, apply_eq: bool = True) → list[ndarray[Any, dtype[Real]]][source]

Generate pulse responses for all networks.

Keyword Arguments:

  • chnls – The list of networks to generate pulse responses for. Default: None (i.e. - Use self.chnls.)

  • Hctf – Complex voltage transfer function of CTLE. Default: None (i.e. - Calculate, using self.gDC & self.gDC2.)

  • tx_ix – Desired Tx tap weights index. Default: None (i.e. - Use self.tx_ix.)

  • rx_taps – Desired Rx FFE tap weights. Default: None (i.e. - Use self.rx_taps.)

  • dfe_taps – Desired Rx DFE tap weights. Default: None (i.e. - Use self.dfe_taps.)

  • apply_eq – Include linear EQ when True; otherwise, exclude it. (Allows for pulse response generation of terminated, but unequalized, channel.) Default: True

Returns:

list of pulse responses.

Notes

1. Assumes self.gDC, self.gDC2, self.tx_taps, self.rx_taps, and self.dfe_taps have been set correctly, if the equivalent function parameters have not been provided.

2. To generate pulse responses that include all linear EQ except the Rx FFE/DFE (i.e. - pulse responses suitable for Rx FFE/DFE tap weight optimization, via either optimize.przf() or optimize.mmse()), set rx_taps equal to: [1.0] and dfe_taps equal to: [].

calc_fom(tx_ix: int, Hctf: ndarray[Any, dtype[Comp]], rx_taps: ndarray[Any, dtype[Real]] | None = None, opt_mode: OptMode | None = None, norm_mode: NormMode | None = None, unit_amp: bool | None = None, n_pre: int | None = None) → float[source]

Calculate the figure of merit (FOM), given the existing linear EQ settings. Optimize Rx FFE taps if they aren’t specified by caller.

Parameters:

  • tx_ix – Index into the list of Tx tap weight combinations.

  • Hctf – Complex voltage transfer function of CTLE.

Keyword Arguments:

  • rx_taps – Rx FFE tap weight overrides. Default: None (i.e. - Optimize Rx FFE tap weights.)

  • opt_mode – Optimization mode. Default: None (i.e. - Use self.opt_mode.)

  • norm_mode – The tap weight normalization mode to use. Default: None (i.e. - Use self.norm_mode.)

  • unit_amp – Enforce unit pulse response amplitude when True. (For comparing optimize.przf() results to optimize.mmse() results.) Default: None (i.e. - Use self.unit_amp.)

  • n_pre – Number of pre-cursor taps to use in calculating ISI. Default: None (i.e. - Use self.nRxPreTaps.)

Returns:

The resultant figure of merit.

Notes

  1. See: IEEE 802.3-2022 93A.1.6.

  2. Unlike other member functions of the COM class, this function optimizes the Rx FFE tap weights when they are not provided.

opt_eq(do_opt_eq: bool = True, tx_taps: ndarray[Any, dtype[Real]] | None = None, opt_mode: OptMode | None = None, norm_mode: NormMode | None = None, unit_amp: bool | None = None) → bool[source]

Find and set the optimum values for the linear equalization parameters: c[n], gDC, gDC2, and w[n] as per IEEE 802.3-22 93A.1.6 (or, [1] slide 11 if MMSE has been chosen).

Keyword Arguments:

  • do_opt_eq – Perform optimization of linear EQ when True. Default: True

  • tx_taps – Used when do_opt_eq = False. Default: None

  • opt_mode – Optimization mode. Default: None (i.e. - Use self.opt_mode.)

  • norm_mode – The tap weight normalization mode to use. Default: None (i.e. - Use self.norm_mode.)

  • unit_amp – Enforce unit pulse response amplitude when True. (For comparing przf() results to mmse() results.) Default: None (i.e. - Use self.unit_amp.)

Returns:

True if no errors encountered; False otherwise.

Notes

  1. The found optimum equalization values are set for the instance.

calc_noise(cursor_ix: int | None = None) → tuple[float, float, int][source]

Calculate the interference and noise for COM.

Keyword Arguments:

cursor_ix – An optional predetermined cursor index, to be used instead of our own estimate. (In support of MMSE.) Default: None

Returns:

A triplet containing

  • signal amplitude (V)

  • noise + interference amplitude (V)

  • cursor location within victim pulse response vector

Notes

  1. Assumes the following instance variables have been set optimally:

    • gDC

    • gDC2

    • tx_ix

    • rx_taps

    (This assumption is embedded into the gen_pulse_resps() function.)

  2. Fills in the com_results dictionary w/ various useful values for debugging.

about_str = '\n      <H2><em>PyChOpMarg</em> - A Python implementation of COM, as per IEEE 802.3-22 Annex 93A/178A.</H2>\n\n      <strong>By:</strong> David Banas <capn.freako@gmail.com><p>\n\n      <strong>On:</strong> January 20, 2025<p>\n\n      <strong>At:</strong> v3.1.0\n\n      <H3>Useful Links</H3>\n\n      (You\'ll probably need to: right click, select <em>Copy link address</em>, and paste into your browser.)\n        <UL>\n\n          <LI><a href="https://github.com/capn-freako/PyChOpMarg"><em>GitHub</em> Home</a>\n          <LI><a href="https://pypi.org/project/PyChOpMarg/"><em>PyPi</em> Home</a>\n          <LI><a href="https://readthedocs.org/projects/pychopmarg/"><em>Read the Docs</em> Home</a>\n        </UL>\n    '