SubGHz Signal Generator by RocketGod 📡🔬

July 16, 2025 · View on GitHub

This SubGHz Signal Generator for the Flipper Zero, made by RocketGod, is a comprehensive RF testing tool for generating various signal types across multiple radio frequencies and modulation schemes. Below is an in-depth look at each mode, from its technical details to practical applications in RF testing and development.

🎥 Internal CC1101 Demonstration

https://github.com/user-attachments/assets/4a34bc73-d419-480e-bb87-90216eb8a1e0

🎥 External CC1101 Demonstration

https://github.com/user-attachments/assets/1053ec27-a15f-4313-9257-2360135c5e96

🎥 Modulation Modes

https://github.com/user-attachments/assets/77970e50-d46f-4d59-bbb0-6e2624a98127

🧪 Signal Analysis Examples

🧪 Reference Signal: Car Fob in Controlled Lab Test (-28dBm)

car_fob

🧪 Community .sub files in Controlled Lab Test (-8dBm narrow)

signal_sub_files

🧪 Signal Generator App and Internal CC1101/Antenna in Controlled Lab Test (-8dBm wide)

rocketgod_signal_gen_app

🧪 Signal Generator App and External CC1101/Antenna Flux Capacitor by Rabbit Labs (10dBm) [TinySA Ultra hard wired w/25W attenuator]

External_Flux-Capacitor_Rabbit-Labs

https://github.com/user-attachments/assets/53a3123e-b749-4af6-b542-e1784b131084

📡 External CC1101 Notes

📡 Frequency Control

The app supports multiple frequency bands within the sub-GHz spectrum:

  • Band 1: 300 MHz – 348 MHz
  • Band 2: 387 MHz – 464 MHz
  • Band 3: 779 MHz – 928 MHz

You can adjust frequencies with precision:

  • Left/Right arrows move between digits to adjust.
  • Up/Down arrows increase or decrease the selected digit.

The app will automatically correct the frequency if it's outside the valid range for the selected band.

⚙️ Signal Generation Modes

Each mode generates distinct modulation schemes and data patterns for testing various RF systems and protocols.

🦾 OOK 650 kHz (On-Off Keying):

  • Pattern: A continuous stream of 0xFF (all bits set to 1).
  • Technical Details: OOK modulation where carrier presence/absence represents binary data.
  • Applications: Testing OOK receivers, analyzing sensitivity to continuous carrier signals, evaluating AGC behavior in simple RF systems.

⚡ 2FSK 2.38 kHz (Frequency Shift Keying):

  • Pattern: Alternates between 0xAA (10101010) and 0x55 (01010101).
  • Technical Details: Narrow deviation FSK with 2.38 kHz frequency separation.
  • Applications: Testing narrowband FSK receivers, evaluating demodulator performance, analyzing channel selectivity.

🔥 2FSK 47.6 kHz:

  • Pattern: Alternates between 0xAA and 0x55.
  • Technical Details: Wide deviation FSK with 47.6 kHz frequency separation.
  • Applications: Testing wideband FSK systems, evaluating adjacent channel rejection, analyzing capture effect in FM receivers.

💥 MSK 99.97 Kb/s (Minimum Shift Keying):

  • Pattern: Random data stream.
  • Technical Details: Continuous phase modulation with minimal frequency deviation.
  • Applications: Testing high-speed digital links, evaluating BER performance, analyzing spectral efficiency of communication systems.

📶 GFSK 9.99 Kb/s (Gaussian Frequency Shift Keying):

  • Pattern: Random data stream.
  • Technical Details: FSK with Gaussian pulse shaping for reduced spectral occupancy.
  • Applications: Testing Bluetooth/BLE systems, evaluating low-power RF links, analyzing modulation quality.

🚀 Pattern 0xFF:

  • Pattern: Continuous 0xFF bytes.
  • Technical Details: Unmodulated carrier or continuous high state.
  • Applications: Testing receiver saturation points, evaluating RF front-end linearity, measuring blocking performance.

🎶 Sine Wave:

  • Pattern: Pure sinusoidal waveform.
  • Technical Details: Continuous wave (CW) signal generation.
  • Applications: Calibrating RF equipment, testing filter responses, evaluating receiver sensitivity.

🟥 Square Wave:

  • Pattern: Alternating high/low states.
  • Technical Details: Digital pulse train with sharp transitions.
  • Applications: Testing digital demodulators, analyzing rise/fall time effects, evaluating pulse detection systems.

📈 Sawtooth Wave:

  • Pattern: Linear ramp followed by sharp drop.
  • Technical Details: Asymmetric waveform with gradual frequency changes.
  • Applications: Testing PLL lock range, evaluating frequency tracking systems, analyzing sweep responses.

🎲 White Noise:

  • Pattern: Random amplitude values across spectrum.
  • Technical Details: Uniform spectral density noise generation.
  • Applications: SNR testing, evaluating noise figure, analyzing system noise immunity.

🔺 Triangle Wave:

  • Pattern: Symmetric linear transitions.
  • Technical Details: Continuous phase modulation with linear frequency changes.
  • Applications: Testing FM demodulators, evaluating linearity, analyzing harmonic content.

📡 Chirp Signal:

  • Pattern: Frequency sweep within burst.
  • Technical Details: Linear frequency modulation over time.
  • Applications: Testing radar systems, evaluating frequency agility, analyzing dispersive channels.

🎲 Gaussian Noise:

  • Pattern: Gaussian-distributed random values.
  • Technical Details: Noise with bell-curve amplitude distribution.
  • Applications: Realistic noise floor simulation, BER testing, evaluating error correction performance.

💥 Burst Mode:

  • Pattern: Periodic high-intensity bursts.
  • Technical Details: Pulsed transmission with controlled duty cycle.
  • Applications: Testing packet reception, evaluating AGC response time, analyzing burst synchronization.

🎛️ Controls

  • Up/Down Buttons: Modify the currently selected digit in the frequency.
  • Left/Right Buttons: Move between digits to adjust frequency values.
  • OK Button: Switch signal generation modes in real-time.
  • Back Button: Stop signal generation and exit the app.

🔬 Use Cases

  1. RF System Testing: Generate test signals to evaluate receiver performance
  2. Protocol Development: Test new modulation schemes and data patterns
  3. Education: Learn about different RF modulation techniques
  4. Equipment Calibration: Use CW signals for calibrating RF test equipment
  5. Interference Analysis: Study how different signal types affect RF systems
  6. Research: Explore sub-GHz spectrum characteristics

This tool is designed for legitimate RF testing, research, and educational purposes. Users must:

  • Ensure compliance with local RF regulations
  • Use only in controlled environments or with proper authorization
  • Respect spectrum allocation and avoid interference with licensed services
  • Understand that improper use may violate telecommunications laws

Note: This is a signal generator for testing and development purposes. It should only be used by qualified individuals in appropriate settings with proper authorization.

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