// SAME Analog Modular Ecosystem
//
// / SPDX-FileCopyrightText: 2026 Denis Chevalier <perso@denischevalier.fr>
// / SPDX-License-Identifier: CC-BY-SA-4.0
// / SPDX-License-Identifier: CERN-OHL-S-2.0+
// / SPDX-License-Identifier: GPL-3.0-or-later
//
// The prose, explanatory text, rendered figures, tables, and mathematical
// content of this specification are licensed under CC BY-SA 4.0. If a later
// version of CC BY-SA is published, the author grants permission to distribute
// this work under that later version as well.
//
// Hardware designs contained herein (schematics, PCB layouts, mechanical
// drawings, and CAD models) are licensed under CERN-OHL-S-2.0+.
//
// All executable code, helper libraries (`lib/*`), metrology assertions, and
// embedded verification scripts throughout the source documents are licensed
// under the GNU General Public License v3.0 or later (GPL-3.0-or-later).

#import "../lib/unify.typ": qty, unit
#import "@preview/cetz:0.5.2"
#import "@preview/cetz-plot:0.1.4": plot

#figure(
  cetz.canvas({
    import cetz.draw: *

    plot.plot(
      size: (12, 6),
      x-mode: "log",
      x-label: [Frequency $f$ ($unit("Hz")$)],
      y-label: [Coupled Voltage $V_"coupled"$ ($unit("mV")$)],
      x-min: 10,
      x-max: 100000,
      y-min: 0.001,
      y-max: 65,
      x-grid: "minor",
      y-grid: "minor",
      {
        // 20 kHz System Bandwidth limit vertical reference line
        plot.add(
          ((20000, 0.001), (20000, 100)),
          style: (
            stroke: (paint: luma(120), thickness: 0.8pt, dash: "dashed"),
          ),
          label: none,
        )

        // Unshielded PCB trace: C_mutual = 1 pF, Z_victim = 10 kOhm
        plot.add(
          style: (stroke: (dash: "solid")),
          label: [Unshielded trace \
            ($qty(1, "pF"), qty(10, "kilo ohm")$)],
          domain: (10, 100000),
          samples: 1000,
          f => 2 * calc.pi * f * 1e-12 * 10000 * 10 * 1000, // in mV
        )

        // Low-impedance node: C_mutual = 1 pF, Z_victim = 1 kOhm
        plot.add(
          style: (stroke: (dash: "dashed")),
          label: [Low-impedance node \
            ($qty(1, "pF"), qty(1, "kilo ohm")$)],
          domain: (10, 100000),
          samples: 1000,
          f => 2 * calc.pi * f * 1e-12 * 1000 * 10 * 1000, // in mV
        )

        // Guard trace shielding: C_mutual = 0.05 pF, Z_victim = 10 kOhm
        plot.add(
          style: (stroke: (dash: "dotted")),
          label: [Guard trace shielded \
            ($qty(0.05, "pF"), qty(10, "kilo ohm")$)],
          domain: (10, 100000),
          samples: 1000,
          f => 2 * calc.pi * f * 0.05e-12 * 10000 * 10 * 1000, // in mV
        )
      },
    )
  }),
  caption: [Capacitive crosstalk coupled voltage ($V_"coupled"$) vs. frequency across different PCB layout conditions, demonstrating the $qty(20, "decibel per decade")$ slope up to the $qty(20, "kHz")$ system bandwidth boundary],
) <figure-crosstalk-mathematical-model>