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Live View

The Live View feature provides continuous real-time waveform display, allowing you to monitor signals as they change. This guide covers how to use Live View effectively.

Overview

Live View continuously captures and displays waveforms from your oscilloscope, creating a real-time visualization similar to the oscilloscope's own screen but with additional features and customization options.

Key Features

  • High Frame Rate: Up to 1000+ fps with PyQtGraph
  • Low Latency: Minimal delay between capture and display
  • Multi-Channel: Display up to 4 channels simultaneously
  • Auto-Scaling: Automatic signal amplitude adjustment
  • Continuous Update: Non-stop waveform updates
  • Zero Configuration: Works out of the box

Starting Live View

Using the Toolbar

  1. Click the Live View button (▶️ icon)
  2. Waveforms begin updating automatically
  3. Click again (or press Esc) to stop

Using Keyboard Shortcut

Press Ctrl+L to toggle Live View on/off

Using Menu

View → Live View or check the menu item

Live View Interface

Live View Indicator

When Live View is active:

  • Toolbar Button: Changes to "Stop" (⏸️ icon)
  • Status Bar: Shows "LIVE" indicator
  • FPS Counter: Displays current frame rate
  • Trigger Status: Updates in real-time

Display Updates

Update Cycle:

  1. Oscilloscope captures waveform
  2. Data transferred over network
  3. GUI processes and displays data
  4. Repeat continuously

Frame Rate:

  • With PyQtGraph: 100-1000+ fps typical
  • With Matplotlib: 10-30 fps typical
  • Depends on: Network speed, timebase, enabled channels

Performance Optimization

High-Performance Mode (PyQtGraph)

When PyQtGraph is installed, the GUI automatically uses it for optimal performance:

# Install for high-performance Live View
pip install "SCPI-Instrument-Control[gui]"

Benefits:

  • 10-100x faster rendering
  • Smooth, fluid updates
  • GPU acceleration (when available)
  • Lower CPU usage
  • Support for higher frame rates

Verification:

  • Check console on startup
  • Should see: "Using PyQtGraph for waveform display (high performance mode)"
  • Status bar shows higher FPS values

Standard Mode (Matplotlib)

If PyQtGraph is not available, the GUI falls back to matplotlib:

Characteristics:

  • Lower frame rates (10-30 fps)
  • Higher CPU usage
  • Still fully functional
  • All features available

When to Use:

  • PyQtGraph incompatible with system
  • Troubleshooting display issues
  • Preference for matplotlib rendering

Optimizing Performance

1. Reduce Number of Channels

Only enable channels you need:

Fewer channels = Higher frame rate
  • 1 channel: Fastest
  • 2 channels: Still fast
  • 4 channels: Slower but usable

2. Adjust Timebase

Shorter timebase = less data = faster transfer:

  • Fast: 1µs/div - 10µs/div
  • Medium: 100µs/div - 1ms/div
  • Slower: 10ms/div - 1s/div

3. Network Connection

  • Use Gigabit Ethernet for best performance
  • Minimize network hops
  • Direct connection preferred
  • Reduce network traffic

4. Close Unnecessary Panels

Hide panels you're not using:

  • Terminal window
  • VNC viewer
  • Measurement panels (if not needed)

5. Reduce Display Complexity

  • Disable grid if not needed
  • Hide legend
  • Minimize markers
  • Simple display = faster rendering

Live View Controls

Start/Stop

Start Live View:

  • Click "Live View" button
  • Press Ctrl+L
  • View menu → Live View

Stop Live View:

  • Click "Stop" button
  • Press Ctrl+L again
  • Press Esc

Auto-Scaling

Enable Auto-Scale:

  • Tools → Auto Scale
  • Right-click display → Auto Scale
  • Automatically adjusts voltage scales to fit signal

Behavior:

  • Monitors signal amplitude
  • Adjusts voltage scale when needed
  • Maintains optimal display
  • Updates automatically during Live View

Frame Rate Display

Located in status bar:

FPS: 45

Interpretation:

  • 100+: Excellent performance
  • 30-100: Good performance
  • 10-30: Adequate performance
  • <10: Consider optimization

Latency Display

Shows network delay:

Latency: 25 ms

Typical Values:

  • <50ms: Excellent
  • 50-100ms: Good
  • 100-200ms: Acceptable
  • >200ms: Check network

Display Modes in Live View

Normal Mode (Default)

All enabled channels displayed:

  • Automatic vertical stacking
  • Shared time axis
  • Independent voltage scales
  • Color-coded channels

Overlay Mode

All channels overlaid on same axes:

  • Easier comparison
  • Shared voltage and time axes
  • Good for phase relationships
  • May be cluttered with many channels

To Enable:

  • Right-click display → Overlay Mode
  • Or View menu → Display Mode → Overlay

Split View Mode

Separate subplot for each channel:

  • Independent voltage and time axes
  • More screen real estate per channel
  • Easier to see individual details
  • Good for unrelated signals

To Enable:

  • Right-click display → Split View
  • Or View menu → Display Mode → Split View

Live View Features

Real-Time Measurements

Measurements update continuously in Live View:

To Use:

  1. Add measurements in Measurements tab
  2. Enable statistics for tracking
  3. Values update with each frame
  4. Statistics accumulate over time

Example:

Frequency: 1.023 kHz → 1.025 kHz → 1.021 kHz
Vpp: 3.14 V → 3.15 V → 3.13 V

Visual Markers

Add markers that track the live waveform:

Voltage Markers:

  • Horizontal lines
  • Show voltage value
  • Follow waveform if snapped

Time Markers:

  • Vertical lines
  • Show time value
  • Fixed to time axis

To Add:

  • Click "Add Marker" button
  • Or right-click display → Add Marker
  • Drag to position

Trigger Status

Trigger status updates in real-time:

  • 🟢 Triggered: Signal triggered successfully
  • 🟡 Armed: Waiting for trigger
  • 🔴 Stopped: Trigger stopped

Useful For:

  • Verifying trigger is working
  • Adjusting trigger level
  • Ensuring stable display

Grid and Cursors

Grid:

  • Toggle with Ctrl+G
  • Matches oscilloscope divisions
  • 14 horizontal × 10 vertical

Cursors:

  • Toggle with Ctrl+R
  • Measure specific points
  • Delta calculations

Capturing from Live View

Quick Capture

While in Live View, press Ctrl+C to:

  1. Freeze current waveform
  2. Stop Live View
  3. Allow analysis of captured data
  4. Save if desired

Continuous Capture

Keep Live View running while capturing to file:

Using Batch Capture:

  1. Tools → Capture Batch
  2. Set number of captures
  3. Set interval
  4. Specify save location
  5. Live View continues during capture

Example:

  • Capture 100 waveforms
  • 1 second interval
  • Auto-save as NPZ files
  • Monitor Live View throughout

Troubleshooting

Low Frame Rate

Symptoms:

  • FPS <10
  • Jerky updates
  • Slow response

Solutions:

  1. Install PyQtGraph
pip install pyqtgraph
  1. Reduce Channels
  2. Disable unused channels

  3. Fewer channels = faster updates

  4. Reduce Timebase

  5. Use shorter time scale

  6. Less data to transfer

  7. Check Network

  8. Use Gigabit Ethernet
  9. Minimize network distance

  10. Reduce other network traffic

  11. Close Other Apps

  12. Free up CPU/GPU resources
  13. Close unnecessary GUI panels

Display Freezing

Symptoms:

  • Display stops updating
  • FPS drops to 0
  • GUI becomes unresponsive

Solutions:

  1. Stop and Restart Live View
  2. Press Esc to stop
  3. Wait 2 seconds

  4. Press Ctrl+L to restart

  5. Check Connection

  6. Verify oscilloscope still connected
  7. Check network cable

  8. Try disconnect/reconnect

  9. Restart Application

  10. Close GUI
  11. Relaunch
  12. Reconnect to oscilloscope

High CPU Usage

Symptoms:

  • CPU at 80-100%
  • Fan noise
  • System slowdown

Solutions:

  1. Verify PyQtGraph Installed
  2. Check console message on startup

  3. Install if missing

  4. Reduce Frame Rate

  5. Close some channels
  6. Increase timebase

  7. Lower update frequency

  8. Disable Grid

  9. Grid rendering can be expensive

  10. Toggle off with Ctrl+G

  11. Use Normal Mode

  12. Split view uses more resources
  13. Switch to normal mode

Choppy Display

Symptoms:

  • Stuttering updates
  • Inconsistent frame rate
  • Visual jittering

Solutions:

  1. Check Network Latency
  2. View status bar latency
  3. Should be <100ms

  4. Reduce network hops

  5. Disable GPU Acceleration

  6. If GPU is causing issues
  7. File → Preferences → Display

  8. Uncheck "Use GPU acceleration"

  9. Update Graphics Drivers

  10. Outdated drivers can cause issues
  11. Update to latest version

Best Practices

For Monitoring

!!! tip "Continuous Monitoring" - Use AUTO trigger mode - Enable auto-scaling - Add key measurements to table - Enable statistics for trending

For Debugging

!!! tip "Debug Workflow" - Start with AUTO mode to see signal - Switch to NORMAL for stable trigger - Adjust trigger level in real-time - Use visual markers for reference points

For Testing

!!! tip "Test Setup" - Use NORMAL mode for repeatable measurements - Enable all needed measurements - Set up cursors or markers - Capture when event occurs

For Recording

!!! tip "Recording Data" - Use batch capture during Live View - Set appropriate interval - Monitor in Live View - Auto-save to files

Keyboard Shortcuts for Live View

Shortcut Action
Ctrl+L Start/stop Live View
Ctrl+C Capture from Live View
Esc Stop Live View
Ctrl+G Toggle grid
Ctrl+R Toggle cursors
Ctrl+M Add marker
Ctrl+0 Reset zoom
F5 Refresh display

Advanced Live View

With FFT Analysis

Real-Time Frequency Analysis:

  1. Enable Live View
  2. Open FFT tab
  3. Select source channel
  4. FFT updates in real-time
  5. Peaks tracked automatically

Useful For:

  • Monitoring frequency stability
  • Detecting harmonics
  • Tracking spectral changes

With Protocol Decoding

Live Protocol Decode:

  1. Configure protocol decoder
  2. Enable Live View
  3. Decoder processes each frame
  4. Results update in table
  5. Visual overlay on waveform

Useful For:

  • Monitoring bus traffic
  • Debugging communication
  • Verifying data integrity

With Reference Waveforms

Live Comparison:

  1. Save current waveform as reference
  2. Continue Live View
  3. Reference overlaid on live data
  4. See differences in real-time

Useful For:

  • Comparing before/after
  • Tracking signal degradation
  • Quality control

Performance Comparison

PyQtGraph vs Matplotlib

Feature PyQtGraph Matplotlib
FPS (typical) 100-1000+ 10-30
CPU usage Low-Medium Medium-High
GPU acceleration Yes No
Latency Lower Higher
Installation Optional Fallback
Platforms All All

Network Impact

Connection Latency FPS Impact
Direct Gigabit <10ms Minimal
LAN Gigabit 10-50ms Low
LAN 100Mbps 20-100ms Medium
WiFi 50-200ms High
Remote/VPN 100-500ms Very High

Next Steps