Skip to content

Plot Comparer

Overview

The Plot Comparer is a utility designed to plot and overlay multiple data traces acquired from different measurement modules (such as the Spectrum Analyzer, Network Analyzer, or Oscilloscope) onto a single unified graph for detailed comparison and analysis.

To help visualize differences between measurements, it features powerful comparison-assist tools, including manual gain offset adjustments (in dB), dynamic X-axis shifts (for frequency or time), dual Y-axis mapping (Y1/Y2), logarithmic scale toggles (Log X/Log Y), and a "Normalize" function to align peaks automatically.

Key Features

  • Hierarchical Trace Management (Tree View)
    • Displays imported traces in a structured tree. You can easily rename a trace by double-clicking its name.
    • Trace Customization: Adjust line width and choose custom colors for individual traces to enhance distinction.
    • Allows you to toggle the visibility of each trace as a whole, or toggle individual components separately (such as primary Y1 data or secondary Y2 phase/distortion data).
  • Powerful Alignment and Adjustments
    • Gain Offset (dB): Allows you to manually apply a vertical offset to a trace's amplitude, making it easy to align curves visually.
    • Y-Axis Offset: Applies a linear vertical shift to the trace, useful for aligning data in the time or amplitude domains.
    • Invert Polarity: Flips the waveform vertically (multiplies by -1), which is particularly helpful for analyzing out-of-phase signals in the time domain.
    • Axis Shift (Frequency/Time Shift): Shifts a trace horizontally along the X-axis (in Hz for frequency, or seconds for time) to compensate for phase shifts or timing offsets.
    • Normalize (Align Peaks): Automatically aligns the maximum peak of all checked traces, simplifying the comparison of frequency response shapes and peak positions.
  • Full Secondary Y-Axis (Y2) Support
    • Map different physical dimensions within a single trace (e.g., gain and phase, or amplitude and distortion) to the left Y-axis (Y1) and right Y-axis (Y2) independently.
  • Import / Export
    • Import measurement traces captured from other modules, or export your adjusted/compared traces as JSON files to save them for future use.
  • Interactive Cursor & Global Readout
    • Hovering your mouse over the plot dynamically overlays red dashed vertical and horizontal cursor lines.
    • Automatically interpolates Y-values (Y1 and Y2) for all active traces at the current cursor X-position, displaying a clear list of values in the status panel below the plot.

How to Use

Importing and Managing Data

  1. Add Traces from Measurement Modules: Use the "Send to Comparison" feature inside individual measurement modules (e.g., Network Analyzer) to dispatch captured data directly to the Plot Comparer.
  2. Import File Button: Directly load previously exported trace data (JSON format) from your local filesystem.
  3. Delete / Clear All Buttons: Remove the currently selected trace from the tree, or wipe all loaded traces at once.
  4. Export Selected Button: Open the Export Dialog to save specific selected traces (or all checked traces if none are selected) to local files.

Export Options

When exporting traces using the Export Selected Button, you will be presented with several options:

  • Export Targets:
    • Choose which traces to export (selected traces only, all checked traces, or all loaded traces).
  • Export Scheme:
    • Combine into a single file: Export all chosen traces into a single comprehensive JSON or CSV file.
    • Export as individual files: Automatically generate separate files for each trace in a selected directory.
  • Format Options:
    • JSON: Highly detailed export including raw data arrays, axis definitions, and metadata. You can opt to compress the JSON to save space.
    • CSV: Spreadsheet-compatible export. You can customize the delimiter (comma or tab) and data layout (merged on a common X-axis with interpolation, or independent columns).

Adjusting Range and Scale (Plot Range)

  • X / Y1 / Y2 Axis Settings:
    • Auto: Automatically scales the axes so that all checked traces fit perfectly within the visible plot area.
    • Log X / Y Axis: Displays the X-axis or Y1-axis in logarithmic scale. When analyzing frequency response traces, Log X is automatically enabled by default.
    • Min / Max Spin Boxes: Turn "Auto" off to lock or manually fine-tune the boundaries (minimum/maximum values) of each axis.
  • Normalize (Align Peaks):
    • When you only want to compare the overall shape of amplitude responses, check this option to automatically shift all traces so their peaks align at 0 dB (or equivalent reference).

Toggling the Control Panel

  • Click the sleek collapse button (‹ or ›) on the right side of the plot to hide the control panel, maximizing the visible graph area.