TETRA Receiver (RTL-SDR)

August 17, 2025 · View on GitHub

📌 Overview

This project implements a TETRA DMO receiver using an RTL-SDR device, GNU Radio, and custom Python/C++ blocks.
It can demodulate and decode signals from a TETRA handset and stream live audio to a PC.

This work was carried out as part of a graduation thesis project at HUST (Vietnam), where I mentored two BSEE students.

🛠️ Features

  • Real-time demodulation and decoding of TETRA DMO signals
  • Audio stream output to PC speakers
  • Custom GNU Radio blocks in Python and C++
  • Tested with live RF signals from a TETRA handset

🔧 Tools & Technologies

  • Hardware: RTL-SDR USB dongle
  • Software: GNU Radio, Python, C++
  • OS: Linux (Ubuntu recommended)
  • Protocols: TETRA DMO

🚀 How to Run

  1. Clone this repo: 
    git clone https://github.com/yourusername/tetra-receiver.git---
  2. Install dependencies (GNURadio Companion, Python libraries, C++ build tools).
  3. Connect the RTL-SDR device.
  4. Run the GNU Radio flowgraph / custom block pipeline.

📊 Results

  • Successfully demodulated and decoded signals from a TETRA handset
  • Live audio streamed to PC speakers

📚 Learning & Contribution

This project demonstrates knowledge in:

  • RF signal processing

  • SDR hardware/software integration

  • Digital communications protocols

  • Software development (Python, C++)

  • System prototyping and validation

  • Mentorship / collaboration (if applicable)

Additional notes

The repo consists of 2 main programs.

1. DMO Decoder

Fork from tetra-kit decoder and modify to include option to decode DMO tetra signal from file

Chạy chương trình với command line option -D để chạy DMO mode. ./decoder -D -d n -i /path/filname options: -d n với n=1, 4 để các level debug khác nhau (sẽ output dữ liệu ra màn hình)

compile bằng lệnh make với makefile default đã có sẵn.

Các file dữ liệu mẫu để test: RxDMO_pluto_390mhz_s36kBit.uint8 plutoDMO_bits.uint8 rtlsdrTMO_bits.uint8

khi chạy decoder, speech audio data sẽ được ghi ra file .out với tên file được generate tự động, và lưu vào subfolder /audio. File .out này là các tetra audio frame (tương ứng với 30ms), cần chạy Tetra speech decoder để chuyển đổi sang file .wav bằng chương trình out2wave.sh trong tetra-kit/recorder

2. DMO Receiver

A program runs on GNURadio toolkit with custom blocks to demodulate and decode Tetra signal received from Rtl-Sdr receiver.

Refer to https://github.com/ctn008/TetraDMO-Receiver/blob/main/tetraDMO-Receiver%20Design.md