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How do I create and visualize my frequency response plots (Bode and Nyquist) in Pulsenics Analytics?

Plot EIS spectra using markers and follow the recommended order: injection → response → impedance → Nyquist.

Goal

Use the Frequency Response tab in Analytics to visualize EIS spectra (frequency-domain behavior) for selected markers and channels.

Recommended order to view plots

Frequency response plots are different views of the same EIS data. The order matters because it helps you confirm signal quality before interpreting impedance features:

  1. Bode: current magnitude

  2. Bode: voltage magnitude

  3. Bode: impedance magnitude and phase

  4. Nyquist

If something looks off early (injection or response), stop and resolve that before interpreting impedance.

Before you start

  • You have an Analytics page with the relevant experiment(s) loaded.

  • You already created single-time markers for the spectra you want to plot.

  • Know where each signal comes from:

    • Current magnitude comes from the Probe.

    • Voltage magnitude, impedance magnitude, phase, and Nyquist come from the CMU (or a single-channel Probe voltage sense setup if no CMU is used).

Important pitfall
If you try to build voltage-based frequency response plots using Probe current sensing instead of CMU voltage sensing, the results may be meaningless.

1) Open Frequency Response plotting

  1. In Analytics, go to the Frequency Response tab.

  2. Under Select analysis, choose the frequency response plot type you want to generate.

Tip
Make sure your plot is grouped by markers, so each trace corresponds to the marker selections you made earlier.

2) Select what you are comparing (hardware)

Before you apply a plot, you are answering: “Which hardware am I comparing?”

For Bode: current magnitude (injection)

  • Select the Probe(s) that measured the AC current injection (often one Probe per experiment).

For voltage and impedance plots (response and impedance)

  • Select the CMU(s) and the correct channel(s) (or the equivalent voltage sensing hardware if using a single-channel setup).

3) Select what moments you are plotting (markers)

  1. Choose the marker type:

    • Relative markers (if you used relative x-axis)

    • Absolute markers (if you used timestamps)

  2. Select the specific markers (or select all).

This answers: “Which timestamps or spectra am I including?”

4) Plot 1: Bode current magnitude (sanity check)

Question this plot answers

“What AC current did the Probe actually inject at each frequency?”

  1. Select Bode: current magnitude.

  2. Select the relevant Probe(s).

  3. Select your marker type and markers.

  4. Click Apply.

What to look for

  • Injection magnitude should match what you expected across the frequency range.

  • If injection is inconsistent or unexpected, do not interpret impedance yet.

5) Plot 2: Bode voltage magnitude (DUT response)

Question this plot answers

“How did the DUT respond in voltage to the injected current across frequency?”

  1. Select Bode: voltage magnitude.

  2. Select the relevant CMU and channel(s) (or correct voltage sense source).

  3. Keep the same marker selections.

  4. Click Apply.

What to look for

  • Voltage response should be comfortably above the noise floor.

  • If response is very small, you may be noise-limited and may need to adjust settings or setup.

6) Plot 3: Bode impedance magnitude and phase

Questions these plots answer

  • “How does impedance change across frequency?”

  • “Is the behavior resistive, capacitive, or inductive at different time scales?”

  • “Does the data look smooth and consistent down to low frequency?”

  1. Select Bode: impedance magnitude and Bode: phase.

  2. Use the same CMU/channel and marker selections.

  3. Click Apply.

How to interpret phase quickly

  • Near 0°: predominantly resistive

  • Positive phase: inductive behavior (often wiring at high frequency)

  • Negative phase: capacitive behavior (often electrochemistry)

Data quality cue

  • Smooth trends are typically a better sign than highly jagged behavior, especially at low frequencies.

7) Plot 4: Nyquist plot (after signal checks)

Question this plot answers

“What is the impedance trajectory (real vs imaginary) and what shapes emerge?”

  1. Select Nyquist.

  2. Keep the same CMU/channel and marker selections.

  3. Click Apply.

Tips

  • Frequency is not explicit on the axes; hover points to see frequency.

  • Interpret Nyquist after reviewing injection and Bode behavior.

How to interpret shapes (high level)

  • Inductive tail at high frequency can indicate wiring effects.

  • Arcs and linear regions can relate to charge-transfer, transport, or interfacial behavior (interpretation is strongest when paired with the Bode plots).

8) Save plots for deeper analysis

If you plan to do advanced analysis such as:

  • Kramers-Kronig (KK) validation

  • equivalent circuit modeling (ECM)

Make sure to save the frequency response plot. The saved plot is what you will use for those workflows.

9) View everything together using Sync container

If you saved multiple plots into a container:

  1. Click Sync container (refresh) to show all saved plots in that container.

  2. Review plots together in the recommended order:

    • current magnitude → voltage magnitude → impedance magnitude/phase → Nyquist

Verify success

  • Each plot uses the correct sensing source (Probe for current, CMU for voltage and impedance).

  • Marker selections produce the expected number of traces.

  • Current and voltage magnitude look reasonable before impedance interpretation.

  • Saved plots are visible after syncing the container.

Common issues

  • My voltage or impedance plots look wrong: confirm you selected the CMU and correct channel, not the Probe.

  • Markers don’t show up: confirm whether your markers are absolute or relative and select the matching marker type.

  • Too many traces: start by selecting fewer markers or fewer channels to simplify interpretation.

  • Nyquist is confusing: review current magnitude and Bode plots first, then return to Nyquist.

Related workflows

  • Create time-domain plots in Analytics

  • Create markers in Analytics

  • Create bar plots using markers

  • Validate spectra with KK testing (next video)