Real-Time CCIR-520 Compliant HF Channel Simulator

Oregon Hardware-Software Factory manufacture, by special order, a professional-quality real-rime HF channel simulator.
Compare the value of this product against other HF channel simulator offerings costing 20 times more.

An HF channel simulator provides a means to apply repeatable test conditions for a number of purposes:

1. Determining raw bit error rates for communication systems,
2. Determine through-put rates and performance figures for modems,
3. Test and stress protocols,
4. Benchmark equipment,
5. Provides a test bed for hardware and software engineers.

The simulator is set up to work between two test devices, simulating, in real time, the effects the ionosphere in both forward and return paths. This kind of test setup is intended for use at base band (0-3kHz).

For forward error-correcting protocols, a simplex path is needed, while for automatic repeat request protocols and other protocols that sends acknowledgement via the reverse channel, a half-duplex path is required. The simulator can operate in either simplex or half duplex.

Simulated conditions includes several modes:

• pass through,
• flat fading,
• multipath.

For flat fading and multipath conditions, the Watterson model for simulating ionospheric effects is applied. This effectively simulates the compounded effects on several incident rays (typically two) due to influence of Earth's magnetic field, refraction in the ionosphere, and the dynamic motion of the ionosphere (Doppler). This results in the production of realistic amplitude fading and phasing effects with controlled statistical properties.

Behavior of the model is controlled by user-supplied parameters for operating mode, fading rate, Doppler bandwidth. In addition, any level of Gaussian noise may be specified to achieve a particulr signal to noise ratio (SNR).

Simulator Features

1. Implements the Watterson ionospheric model on a 3kHz bandwidth baseband.
2. Real time simulation of a 3 kHz baseband bandwidth, allows testing ARQ protocols.
3. Simulate CCIR conditions for
   • "FLAT",
   • "GOOD",
   • "POOR",
   • "MODERATE",
   • and "FLUTTER FADING".