Simulcast system

The IDAS Simulcast synchronizes multiple repeater sites for seamless wide area repeater coverage using just a pair of frequencies, regardless of the number of repeater sites in the network*. Each repeater site in the system is simply composed of only a network controller, GPS antenna and repeater. No external timing reference unit, no additional modulation unit or other equipment is required.
* The maximum number of sites for an IDAS Simulcast system is 32.

The IDAS Simulcast system sends digital voice and data in 4800 bps using 4-Level FSK, and 6.25 kHz very narrow bandwidth FDMA technology. Symbol duration is about 420 microseconds (μs). This long symbol duration affects very small Inter-Symbol Interference (ISI). As a result, the delay spread tolerance of the IDAS Simulcast system is about 60 μs. The simplicity of a non-linear transmitter and GPS synchronization enables an FDMA digital system to achieve wide repeater coverage as an analog FM simulcast system.

By comparison, the delay spread tolerance of a DMR/P25 Phase 1 system is about 30 μs, the coverage radius is reduced by a similar amount. In a P25 simulcast system, a more complex Linear Simulcast Modulation system is required to maintain a better tolerance to delay spread and for greater repeater coverage.

The IDAS Simulcast system provides mobile communication along a highway or railroad. You can communicate all the way on the same channel.