> For the complete documentation index, see [llms.txt](https://docs.timeinpixels.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.timeinpixels.com/nobe-omniscope/sources/signal-generator.md).

# Signal Generator

The Signal Generator creates synthetic test patterns for calibration, testing, and demonstration purposes. It's useful when you need a consistent reference signal without external hardware.

## Overview

OmniScope includes a GPU-based signal generator that can produce various test patterns:

* SMPTE color bars
* Grayscale ramps
* Resolution charts
* Custom patterns

This is useful for:

* Testing scope functionality
* Calibrating displays
* Demonstrating OmniScope features
* Verifying signal paths

## Connecting

1. Open OmniScope
2. Go to **Input** menu > **Connect to...**
3. Select **Signal Generator**
4. Choose your desired test pattern

## Available Patterns

### SMPTE Color Bars

Standard SMPTE color bar pattern used for broadcast calibration. Includes:

* 75% and 100% color bars
* PLUGE (Picture Line-Up Generation Equipment) pattern
* Reference white and black

### Grayscale Ramp

Linear grayscale gradient for checking gamma and contrast:

* Smooth transitions from black to white
* Useful for verifying waveform linearity

### Resolution Chart

High-frequency patterns for checking resolution and sharpness:

* Line pairs at various frequencies
* Corner-to-corner sharpness verification

### Video Signal Tester

Comprehensive test pattern by Thomas Berglund featuring:

* Color bars with various saturation levels
* Grayscale steps
* Resolution patterns
* Safe area markers

{% hint style="info" %}
The Video Signal Tester pattern was contributed by Thomas Berglund. Thank you!
{% endhint %}

## Settings

| Setting    | Description                                                                                | Default    |
| ---------- | ------------------------------------------------------------------------------------------ | ---------- |
| Pattern    | Which test pattern to generate                                                             | SMPTE Bars |
| Resolution | Output resolution                                                                          | 1920x1080  |
| Frame Rate | Output frame rate — choose from common rates (23.98, 24, 25, 29.97, 30, 50, 59.94, 60 fps) | 30 fps     |
| Bit Depth  | Signal bit depth                                                                           | 10-bit     |

## Use Cases

### Scope Calibration

Use color bars to verify your scopes are displaying accurate values:

* 75% bars should read at specific vectorscope positions
* White should reach 100 IRE on the waveform
* Black should sit at 0 IRE (or 7.5 IRE for NTSC setup)

### Display Calibration

Output test patterns to external monitors via SDI Out to calibrate:

* Brightness and contrast using PLUGE
* Color accuracy using color bars
* Gamma using grayscale ramps

### Demonstrations

When demonstrating OmniScope, the signal generator provides a consistent, reliable source without needing external hardware.

## Tips

* Use 10-bit output for most accurate testing
* The signal generator is GPU-based for low CPU usage
* Combine with SDI Out to send patterns to external displays

## Related

* [SDI Out](/nobe-omniscope/live-pack-add-on/sdi-out.md) - Output test patterns to external devices
* [Waveform](/nobe-omniscope/scopes/waveform.md) - Analyze generated patterns
* [Vectorscope](/nobe-omniscope/scopes/vectorscope.md) - Verify color bar accuracy