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Circuit transient analysis and eye diagram

This example shows how to create a circuit design, run a Nexxim time-domain simulation, and create an eye diagram.

Keywords: Circuit, transient, eye diagram.

Perform imports and define constants

Perform required imports.

import os
import tempfile
import time

import ansys.aedt.core
import numpy as np
from matplotlib import pyplot as plt

Define constants.

AEDT_VERSION = "2024.2"
NG_MODE = False  # Open AEDT UI when it is launched.

Create temporary directory

Create a temporary directory where downloaded data or dumped data can be stored. If you’d like to retrieve the project data for subsequent use, the temporary folder name is given by temp_folder.name.

temp_folder = tempfile.TemporaryDirectory(suffix=".ansys")

Launch AEDT with Circuit

Launch AEDT in graphical mode with the Circuit schematic editor.

circuit = ansys.aedt.core.Circuit(
    project=os.path.join(temp_folder.name, "CktTransient"),
    design="Circuit Examples",
    version=AEDT_VERSION,
    new_desktop=True,
    non_graphical=NG_MODE,
)

PyAEDT INFO: Python version 3.10.11 (tags/v3.10.11:7d4cc5a, Apr  5 2023, 00:38:17) [MSC v.1929 64 bit (AMD64)]
PyAEDT INFO: PyAEDT version 0.12.dev0.
PyAEDT INFO: Initializing new Desktop session.
PyAEDT INFO: Log on console is enabled.
PyAEDT INFO: Log on file C:\Users\ansys\AppData\Local\Temp\pyaedt_ansys_3ac6b15f-aaf6-45a6-a507-29c6953b5bee.log is enabled.
PyAEDT INFO: Log on AEDT is enabled.
PyAEDT INFO: Debug logger is disabled. PyAEDT methods will not be logged.
PyAEDT INFO: Launching PyAEDT with gRPC plugin.
PyAEDT INFO: New AEDT session is starting on gRPC port 62453
PyAEDT INFO: AEDT installation Path C:\Program Files\AnsysEM\v242\Win64
PyAEDT INFO: Ansoft.ElectronicsDesktop.2024.2 version started with process ID 2600.
PyAEDT INFO: Project CktTransient has been created.
PyAEDT INFO: Added design 'Circuit Examples' of type Circuit Design.
PyAEDT INFO: Aedt Objects correctly read

Place IBIS buffer

Read an IBIS file and place a buffer in the schematic editor.

ibis = circuit.get_ibis_model_from_file(
    os.path.join(circuit.desktop_install_dir, "buflib", "IBIS", "u26a_800.ibs")
)
ibs = ibis.buffers["DQ_u26a_800"].insert(0, 0)

PyAEDT INFO: ModelerCircuit class has been initialized! Elapsed time: 0m 0sec
PyAEDT INFO: ModelerNexxim class has been initialized!
PyAEDT INFO: Modeler class has been initialized! Elapsed time: 0m 0sec

Place ideal transmission line

Place an ideal transmission line in the schematic and parametrize it.

tr1 = circuit.modeler.components.components_catalog["Ideal Distributed:TRLK_NX"].place(
    "tr1"
)
tr1.parameters["P"] = "50mm"

Place components

Create a resistor and ground in the schematic.

res = circuit.modeler.components.create_resistor(name="R1", value="1Meg")
gnd1 = circuit.modeler.components.create_gnd()

Connect componennts

Connect the components in the schematic.

tr1.pins[0].connect_to_component(ibs.pins[0])
tr1.pins[1].connect_to_component(res.pins[0])
res.pins[1].connect_to_component(gnd1.pins[0])

(True,
 <ansys.aedt.core.modeler.circuits.object_3d_circuit.CircuitComponent at 0x15b3349b3a0>,
 <ansys.aedt.core.modeler.circuits.object_3d_circuit.CircuitComponent at 0x15b3349b730>)

Place a probe

Place a voltage probe and rename it to Vout.

pr1 = circuit.modeler.components.components_catalog["Probes:VPROBE"].place("vout")
pr1.parameters["Name"] = "Vout"
pr1.pins[0].connect_to_component(res.pins[0])
pr2 = circuit.modeler.components.components_catalog["Probes:VPROBE"].place("Vin")
pr2.parameters["Name"] = "Vin"
pr2.pins[0].connect_to_component(ibs.pins[0])

(True,
 <ansys.aedt.core.modeler.circuits.object_3d_circuit.CircuitComponent at 0x15b334c0220>,
 <ansys.aedt.core.modeler.circuits.object_3d_circuit.CircuitComponent at 0x15b334c01f0>)

Analyze

Create a transient analysis setup and analyze it.

trans_setup = circuit.create_setup(name="TransientRun", setup_type="NexximTransient")
trans_setup.props["TransientData"] = ["0.01ns", "200ns"]
circuit.analyze_setup("TransientRun")

PyAEDT INFO: Key Desktop/ActiveDSOConfigurations/Circuit Design correctly changed.
PyAEDT INFO: Solving design setup TransientRun
PyAEDT INFO: Key Desktop/ActiveDSOConfigurations/Circuit Design correctly changed.
PyAEDT INFO: Design setup TransientRun solved correctly in 0.0h 0.0m 6.0s

True

Create report

Create a report using the get_solution_data() method. This method allows you to view and postprocess results using Python packages. The solutions.plot() method uses Matplotlib.

report = circuit.post.create_report("V(Vout)", domain="Time")
if not NG_MODE:
    report.add_cartesian_y_marker(0)
solutions = circuit.post.get_solution_data(domain="Time")
solutions.plot("V(Vout)")

PyAEDT INFO: Post class has been initialized! Elapsed time: 0m 0sec
PyAEDT INFO: Solution Data Correctly Loaded.

Visualize results

Create a report inside AEDT using the new_report object. This object is fully customizable and usable with most of the reports available in AEDT. The standard report is the main one used in Circuit and Twin Builder.

new_report = circuit.post.reports_by_category.standard("V(Vout)")
new_report.domain = "Time"
new_report.create()
if not NG_MODE:
    new_report.add_limit_line_from_points([60, 80], [1, 1], "ns", "V")
    vout = new_report.traces[0]
    vout.set_trace_properties(
        style=vout.LINESTYLE.Dot,
        width=2,
        trace_type=vout.TRACETYPE.Continuous,
        color=(0, 0, 255),
    )
    vout.set_symbol_properties(
        style=vout.SYMBOLSTYLE.Circle, fill=True, color=(255, 255, 0)
    )
    ll = new_report.limit_lines[0]
    ll.set_line_properties(
        style=ll.LINESTYLE.Solid,
        width=4,
        hatch_above=True,
        violation_emphasis=True,
        hatch_pixels=2,
        color=(0, 0, 255),
    )
new_report.time_start = "20ns"
new_report.time_stop = "100ns"
new_report.create()
sol = new_report.get_solution_data()
sol.plot()

PyAEDT INFO: Solution Data Correctly Loaded.

Create eye diagram in AEDT

Create an eye diagram inside AEDT using the new_eye object.

new_eye = circuit.post.reports_by_category.eye_diagram("V(Vout)")
new_eye.unit_interval = "1e-9s"
new_eye.time_stop = "100ns"
new_eye.create()

PyAEDT INFO: Parsing C:/Users/ansys/AppData/Local/Temp/tmpka6wj8va.ansys/CktTransient.aedt.
PyAEDT INFO: File C:/Users/ansys/AppData/Local/Temp/tmpka6wj8va.ansys/CktTransient.aedt correctly loaded. Elapsed time: 0m 0sec
PyAEDT INFO: aedt file load time 0.01561737060546875

True

Create eye diagram in Matplotlib

Create the same eye diagram outside AEDT using Matplotlib and the get_solution_data() method.

unit_interval = 1
offset = 0.25
tstop = 200
tstart = 0
t_steps = []
i = tstart + offset
while i < tstop:
    i += 2 * unit_interval
    t_steps.append(i)

t = [
    [i for i in solutions.intrinsics["Time"] if k - 2 * unit_interval < i <= k]
    for k in t_steps
]
ys = [
    [
        i / 1000
        for i, j in zip(solutions.data_real(), solutions.intrinsics["Time"])
        if k - 2 * unit_interval < j <= k
    ]
    for k in t_steps
]
fig, ax = plt.subplots(sharex=True)
cells = np.array([])
cellsv = np.array([])
for a, b in zip(t, ys):
    an = np.array(a)
    an = an - an.mean()
    bn = np.array(b)
    cells = np.append(cells, an)
    cellsv = np.append(cellsv, bn)
plt.plot(cells.T, cellsv.T, zorder=0)
plt.show()

Release AEDT

Release AEDT and close the example.

circuit.save_project()
circuit.release_desktop()
# Wait 3 seconds to allow AEDT to shut down before cleaning the temporary directory.
time.sleep(3)

PyAEDT INFO: Project CktTransient Saved correctly
PyAEDT INFO: Desktop has been released and closed.

Clean up

All project files are saved in the folder temp_folder.name. If you’ve run this example as a Jupyter notebook, you can retrieve those project files. The following cell removes all temporary files, including the project folder.

temp_folder.cleanup()

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Download this example

Download this example as a Jupyter Notebook or as a Python script.