Mergen Scope is a free, open-source, browser-based viewer for Rohde & Schwarz spectrum analyzer .dat files and Touchstone .sNp files. Visualize RF spectrum data, network measurements, and spectral analysis online with no installation required.
- Multi-trace support: load and compare multiple measurements
- Interactive markers: place markers, search for peaks and minima, track frequency points
- Trace Ops panel: create derived traces without changing the raw source
- Multi-pane view: switch between 1 and 4 stacked panes with shared X navigation
- Offset and Scale: additive or multiplicative amplitude correction as derived traces
- Smoothing: None, Moving Average, Median Filter, and Savitzky-Golay
- Trace Math:
A + B,A - B,A * B,A / Bwith overlap-only math on A's grid - Interpolation control for trace math: Auto, Exact only, Linear, Nearest, Previous, Next, Cubic spline
- Trace Math warnings: short unit-aware warning notes for logarithmic and mixed-logarithmic math, with no blocking and no automatic unit conversion
- Noise PSD panel: visualize noise power spectral density across the spectrum
- IP3/TOI measurement tool: marker-driven intermodulation point calculation
- Expanded analysis toolkit: peak/spur table, marker delta table, range statistics, bandwidth helper, threshold crossings, ripple/flatness, occupied bandwidth, and guarded channel power
- Touchstone matrix picker: S/Y/Z family selection with per-cell trace generation
- Touchstone analysis toolkit: VSWR, Return Loss, Group Delay, Reciprocity/Isolation, and 2-port stability metrics
- Touchstone stability trace generation: create derived scalar traces for
K,mu1,mu2, and|delta| - Zoom and pan: navigate large frequency ranges with oscilloscope-style division readout
- Saved results: keep Noise PSD and IP3 results inside the current workspace
- Workspace import/export: save and reopen complete sessions as portable JSON
- Data export: download raw traces, derived traces, current Noise PSD analysis trace, and saved analysis results as JSON
- Chart export: capture the current chart view as PNG or SVG
- No installation required: runs in any modern browser
- No CDN dependencies: all libraries are vendored locally and work offline
| Format | Instruments | Notes |
|---|---|---|
R&S semicolon-delimited .dat |
Rohde & Schwarz instruments | Tested |
Amplitude-only .dat |
R&S instruments | Frequency reconstructed from metadata |
Touchstone .s1p to .sNp |
RF network measurements | Supported for S/Y/Z trace workflows and Smith view |
- Smith charts are currently a bit buggy in some workflows. They are complex to implement correctly, and improvements are planned for future updates.
git clone https://github.com/AlpGoXd/mergen-scope.gitOpen mergen_scope.html directly in a modern browser. No build step and no install.
Push to main. GitHub Actions deploys automatically via .github/workflows/deploy-pages.yml.
Click Load File and select a .dat or .sNp export. Use Append to add more traces.
Use Save Workspace to export the current session as JSON, including imported files, derived traces, pane layout, zoom state, markers, reference lines, and saved analysis results.
Use Open Workspace to restore a previously exported session in one step.
Use Export Data to download the current traces as JSON, including raw traces, derived traces, the current Noise PSD analysis trace when available, and saved Noise/IP3 results.
Use PNG or SVG to export the current chart view as an image.
Click the chart to place a marker. Select a marker to make it active, then use Peak, Next Peak, Min, or Next Min to move it to signal features.
Open Trace Ops to create derived traces from existing traces:
- Offset adds a constant value
- Scale multiplies by a constant factor
- Smoothing supports None, Moving Average, Median Filter, and Savitzky-Golay
- Trace Math supports
A + B,A - B,A * B,A / B
Trace Math works over the overlapping X range only, uses A's grid, and offers interpolation control for mapping trace B onto A.
Trace Math also shows short warning-only notes when logarithmic units can make the result misleading. That includes same-unit logarithmic math such as dBm + dBm, dB * dB, and mixed logarithmic-unit math such as dB * dBm. These notes do not block the operation and do not change the math.
Use the Pane controls to switch between:
- 1 Pane for the current single-chart workflow
- up to 4 stacked panes for shared-X comparison with independent Y scaling
In multi-pane mode you can:
- set the active pane
- add or remove panes
- move the selected trace to any pane
- drag a trace row from the sidebar and drop it onto a pane header or pane body
- fit the current pane
- fit all panes
- clear one pane by moving its traces back to another pane
Current first-release behavior:
- X zoom and pan are shared across panes
- Y zoom and fit are pane-local
- marker search follows the active pane and its selected trace
- reference lines are pane-local by default, with an optional lock mode to place linked lines across all panes
Open the Noise PSD panel, set the resolution bandwidth, and the tool computes noise power spectral density from the selected trace.
Assign marker roles (F1, F2, IM3L, IM3U) using the marker panel, then compute IP3 from the marked points.
Open Analysis to access pane-aware numeric tools that act on the selected trace in the active pane over the currently visible range:
- Peak / Spur Table
- Marker Delta Table
- Range Statistics
- 3 dB / 10 dB Bandwidth
- Threshold Crossings
- Ripple / Flatness
- Occupied Bandwidth
- Channel Power with strict unit gating
- VSWR (Touchstone reflection traces)
- Return Loss (Touchstone reflection traces)
- Group Delay (Touchstone traces)
- Reciprocity / Isolation (Touchstone transmission traces)
- Touchstone Stability (2-port, K / mu1 / mu2 / |delta|)
Group Delay is computed from complex S-parameter data as atan2(im,re), frequency in Hz, central-difference derivatives for interior points, and forward/backward differences at the edges. Very low-magnitude regions are masked to avoid unstable phase-derivative spikes.
For 2-port Touchstone traces, the Touchstone Stability card computes stability metrics over the visible range and can generate scalar traces for:
Kmu1mu2|delta|
The card summarizes min/max ranges, center-point values, and whether visible points satisfy unconditional stability checks (K > 1 and |delta| < 1).
Typical R&S semicolon-delimited export:
; R&S Export
Values;1001
StartXAxis;1000000;Hz
StopXAxis;3000000000;Hz
RBW;3000;Hz
Trace 1;
Trace Mode;CLR/WR
Detector;RMS
1000000;-80.5
1030000;-79.2
...
No build step. The app still runs directly in the browser from GitHub Pages using local vendored runtime files under vendor/.
mergen_scope.html is now a thin loader/bootstrap file. It mainly defines the document shell, loads the vendored browser runtime plus local app-modules/*.js files in order, and mounts window.AppController.AppRoot directly.
The app runtime is split across browser-global modules under app-modules/:
app-modules/app-hooks.jsfor extracted React hooks plus helper wiring used by the controllerapp-modules/app-shell-components.jsfor shell UI pieces such as buttons, trace rows, marker/ref-line cards, top bar, and footer componentsapp-modules/app-analysis-components.jsfor the analysis card/component stack used by the right-side analysis panelapp-modules/app-chart-components.jsfor the empty-chart state and chart workspace rendering componentsapp-modules/app-controller.jsfor app orchestration, derived view-model composition, and the browser-mountedAppRoot
The split keeps the no-build architecture intact while moving the high-churn app code out of the HTML entrypoint. The current rules are:
- keep direct file-open support
- keep GitHub Pages compatibility
- keep local plain scripts attached to
window - keep the browser-global module boundary stable
Current helper split:
app-modules/trace-helpers.jsfor chart/window helpersapp-modules/trace-model.jsfor trace identity, units, and axis-label helpersapp-modules/trace-ops-helpers.jsfor smoothing, interpolation, and trace-math helpersapp-modules/analysis-helpers.jsfor Noise PSD, IP3 math, and saved-result shaping helpersapp-modules/analysis-target-helpers.jsfor pane-aware analysis registry, target resolution, and unit gatingapp-modules/range-analysis-helpers.jsfor range stats, crossings, bandwidth, OBW, and channel-power mathapp-modules/file-store-helpers.jsfor trace normalization, dedupe, and file-signature helpersapp-modules/parser-helpers.jsfor nearest-point lookup and R&S.datparsing helpersapp-modules/marker-helpers.jsfor IP3 marker-role helpers and peak/min search mathapp-modules/derived-state-helpers.jsfor derived-trace dependency cleanup helpersapp-modules/ui-helpers.jsfor formatting, theme colors, metric rows, and saved-result item componentsapp-modules/pane-helpers.jsfor pane ownership, per-pane trace filtering, and pane Y-domain helpersapp-modules/workspace-helpers.jsfor workspace snapshot normalization, demo preset restoration, and session import/export payload helpersapp-modules/export-helpers.jsfor chart export rendering and trace/data export package helpersapp-modules/app-hooks.jsfor extracted React hook blocks plus helper wiring previously living inmergen_scope.htmlapp-modules/app-shell-components.jsfor shell UI pieces such as buttons, trace rows, marker/ref-line cards, top bar, and footer componentsapp-modules/app-analysis-components.jsfor the analysis card/component stack used by the right-side analysis panelapp-modules/app-chart-components.jsfor the empty-chart state and chart workspace rendering componentsapp-modules/app-controller.jsfor app orchestration, root composition, and the browser-mountedAppRoot
The app now has a practical raw-vs-derived trace model:
- imported files create immutable raw traces
- Trace Ops creates derived traces
- derived traces keep source-trace references plus operation metadata
- current derived operations include offset, scale, smoothing, and trace math
Current multi-pane model:
- 1 to 4 stacked panes
- shared or pane-local X navigation depending on the
Zoom Alltoggle - independent Y scaling per pane
- pane-local active trace
- pane-local reference lines by default, with optional linked lock mode
- marker and analysis actions act on the selected trace in the active pane
Current sync philosophy:
- no permanent synchronized pane cursor line
- no always-on shared vertical guide line
- future pane synchronization should prefer marker-linked sync or hover-linked readout sync when needed, not a forced global cursor
Current status:
- Phase 3 is complete
- Phase 4 is complete
- Touchstone import support is complete
- Touchstone measurement tools are in active expansion
Roadmap in order:
- First usable multi-pane release Status: completed
- Expanded analysis toolkit Status: completed
- Export and session portability Status: completed Implemented: workspace/session JSON export and import, trace/data export, saved analysis export, and chart PNG/SVG export
- Touchstone import support Status: completed
- Touchstone measurement tools Status: in progress Implemented: Touchstone stability (K, mu1, mu2, |delta|) plus VSWR, Return Loss, Group Delay, and Reciprocity/Isolation cards
- Performance and scaling pass
- Oscilloscope waveform support
Not planned right now:
- a permanent synchronized pane cursor
- an always-on shared pane guide line
- Only tested with R&S
.datexports. Other formats may need parser adjustments - Multi-pane is currently limited to 1 to 4 stacked panes
- Touchstone stability in v1 is 2-port only
- Oscilloscope waveform support is intentionally deferred to a later format-expansion phase
- Pane synchronization does not use a permanent shared cursor line
- Channel power is intentionally gated unless the trace unit is explicit spectral power density such as dBm/Hz or dBW/Hz
- No PWA / offline install support
- Large trace files (>10k points) may affect chart performance
I'm an EE engineer. Like most of us, I don't have time to go deep into React or the rest of the web stack. That's not what I do. But when I went looking for something simple to visualize spectrum analyzer exports and other waveform files in the browser, I couldn't find anything that fit. So I vibecoded this into existence.
Right now it's only been tested with Rohde & Schwarz .dat files, but the goal is to eventually open any type of waveform or instrument export file, online, with no software to install.
Feel free to open issues, suggest changes, and help make this tool better. The aim is to keep it as dependency-free as possible and useful for day-to-day measurement work.
Open an issue or submit a pull request. When testing changes, verify against the regression checklist in the HTML comment at the top of mergen_scope.html.
GNU GPL-3.0-only. See LICENSE.
Alp Gokalp - RF/Microwave Engineering, Analog IC Design