Analog signals have a sinusoidal, or continuous, value. Today’s analog systems use frequency modulation (FM). The frequency modulation produces a continuous wave with the voice signal. By integrating such a simple system into a single chip, the cost of this radio has dramatically reduced. Analog signals are commonly used in many systems today, but the uses for analog signals are declining with the introduction of the more reliable digital signal.
Digital signals are represented by binary numbers: 1 or 0. The 1 and 0 values can correspond to different discrete voltage values. Any signal that doesn’t quite fit into the scheme is rounded off. By using a binary signal, error correction- embedded signaling and control bits are possible in each packet transmitted. A packet contains an assembly of bits. The software contains an algorithm that understands the differences between voice and background noise, and in return, cancels the unwanted background noise and unwanted audio. The wireless digital signal provides the same levels of reliability and control as a wired digital signal.
IP / WIFI / ROIP
License-free radio for wireless networks (WLAN)
Radio systems for wireless networks bridge the gap between license-free and licensed radio devices. The system can be connected to an existing WLAN network and allows full duplex communication with reliable sound quality.
WLAN-based radio systems offer scalable, license-free communication that uses standardized wireless network products as infrastructure. In several cases, said infrastructure is already in place.
Satellite phones are a type of mobile phone that connects to orbiting satellites instead of terrestrial cell sites. They provide similar functionality to terrestrial mobile telephones; voice, short messaging service and low-bandwidth internet access are supported through most systems.
Depending on the architecture of a particular system, coverage may include the entire Earth, or only specific regions.