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RX (Receiver) Sensitivity
Digi radio modems can “hear” signals that most modems cannot.
Receiver sensitivity is a measure of the weakest signal a radio is able to detect and demodulate. Superior RX sensitivity helps overcome many of the challenges inherent to RF communication systems - such as signal attenuation (degradation).
Digi’s research has shown the average receiver sensitivity for modems in the wireless device market is a mere -93 dBm. Because of superior RX sensitivity, Digi radio modems (RX sensitivity ranges from -100 dBm to -114 dBm) achieve up to 8 times the range of competing radios. This enables OEMs and integrators to cover more ground with fewer radios.
Range gained through Digi receiver sensitivity
(other system variables held equal)
XII™ interference blocking
XStream Interference Immunity™ (XII™) technology is a proprietary hardware and software feature set that allows system designers to create wireless systems that are immune to most RF interferers (cell phones, pagers, other wireless systems, etc.).
When operating within the 900 MHz and 2.4 GHz frequency bands, cell phones, pagers and other wireless systems can dramatically interfere with wireless links. Digi's XII technology provides our modems with up to 60 dB of interference blocking. This means that when two Digi RF modems are communicating at long distances and are near sensitivity level signals, interfering signals just 1 MHz away can be 60 dB (1 million times) stronger than the Digi signal and only degrade the receiver sensitivity by 3 dB.
Digi products also utilize frequency hopping spread spectrum (FHSS) communication that, by design, delivers additional protection against interference.
The XII interference-blocking feature ships in all Digi data radio modems.
TX (Transmit) Power Output
As is the case with RX (Receiver) Sensitivity, TX Power Output can greatly increase the range of a wireless link. To accommodate a wide range of wireless needs, Digi offers the following TX power output options:
The preceding specifications represent the amount of power that comes out of the radio modem. EIRP power output measures also include antenna gain and can extend TX Output. For example, the TX output of XTend product family can reach 4 Watts EIRP when used with a 6 dB gain antenna.
This article describes how Digi RF products are designed to have good out-of-band interference rejection from other sources of RF emissions 1MHz or more away from the frequency in which the Digi RF product is designed to operate. An out-of-band interfering radio is one that is intended to broadcast in one frequency but has RF energy that bleeds-over to affect a second radio operating on a different frequency. Final performance can still vary at any particular installation site dependent on both the physical environment in which the radio is installed and the amount of in-band and out-of-band interference sources broadcasting in that same localized area.