Choose a topic or Scroll to read all: Repeater Info, Mobile Info, Portable Info, Operating Modes, Advantages to using Nexedge Digital Radios
NEXEDGE® systems support the following NXDN® digital modes: In addition, NEXEDGE® equipment can support legacy analog modes. Digital Conventional ModeNXR-700/800 base units include a 16-RAN(Radio Access Number) capacity conventional repeater controller for 16 user group site sharing. The 65,519 (each) Group ID and Unit ID capacity adds group and individual selective calling capability beyond conventional analog. Also Mixed mode operation allows analog & NXDN® conventional units to share the same RF channel. Digital Trunked ModeNEXEDGE® trunked mode provides increased capacity, enhanced call capabilities, improved security and faster communications with less required user operation than conventional systems. The system automatically assigns channels for faster, efficient use of spectrum, allowing users to concentrate on the job at hand. The 3,000 (each) Unit ID and Group ID per-site capacity provides ample unit and fleet organization capabilities. Group and Individual calls enjoy complete privacy as other users in the system cannot monitor the calls. The Priority Monitor feature will monitor for up to 4 high priority talk groups and switch users to those calls in progress so important calls are not missed. During peak usage hours, system Call Queuing stacks call requests and processes calls when a channel becomes available. System operators can assign important individuals higher queue priority and even pre-empt lower priority users for more important dispatch and emergency calls. Digital Trunked Wide Area IP NetworksThe network option leverages the power of IP to link up to 16 digital trunked sites together for wide area roaming and calling capabilities. Scalable networks can be created over existing IT assets, private microwave, spread-spectrum links or carrier services using standard 10/100 Base-T Ethernet switches and routers. IP Sec VPN tunneling provides encrypted, secure communications links within any IP network. Subscriber units use advanced control channel hunting algorithms, RF signal strength and digital signal quality (low bit-error-rate) to automatically determine the best sites to register on while moving throughout a network. The 60,000 Group ID and Unit ID network capacity is sufficient for large organizations and multi-user system sharing. The NXDN® Digital AdvantageIn analog systems as the signal strength decreases in low-coverage areas, noise and dropouts increase, severely degrading intelligibility. However, with the NXDN® digital system, which features enhanced Forward Error Correction (FEC), the digitized audio stream is less susceptible to noise, resulting in superior clarity at varying signal strengths. System operators converting from analog to NEXEDGE® typically comment that users now receive calls in areas that were out of range before. NXDN® reduces lost or misinterpreted calls and the need for repeat calls, thus enhancing workforce productivity. (Click to hear the difference ). NXDN®A key element of the NXDN® air interface is the AMBE+2™ vocoder which digitizes speech while retaining natural voice nuances, performs noise reduction, introduces FEC and compresses this voice data to accommodate land mobile radio data rates. Next, the radio's digital signal processor (DSP) protocol- packages the vocoder, signaling, control, and more FEC data together and converts this to a uniquely filtered 4-Level FSK digital waveform that modulates the transmitter. This results in an unusually low bit-error-rate digital air interface delivering robust communications even in weak signal strength areas. The NXDN® air interface is capable of fitting into both narrow 12.5 kHz and very narrow 6.25 kHz bandwidth channels meeting the tightest of spectrum efficiency requirements (9600 bps @ 8.3 kHz and 4800 bps @ 4 kHz occupied bandwidth respectively). NXDN® is a Frequency Division Multiple Access (FDMA) methodology whereby one user accesses a channel frequency at any one point in time (i.e. accesses via the frequency domain). Other digital methods such as Time Division Multiple Access (TDMA) permit more than one user to access the channel frequency via time slots (i.e. accesses via the time domain), but there has to be a tradeoff between coverage and effective transmission rate, as increasing the former means decreasing the latter.
Spectrum EfficientAll NEXEDGE® equipment operates in 25 & 12.5 kHz analog and 12.5 & 6.25 kHz NXDN® digital modes – satisfying spectrum requirements today & tomorrow. Migration by DesignNEXEDGE® extends the life of current radio system assets. All NXDN® digital modes use the same Class-C power amplifiers and site management equipment used for current analog stations, ensuring return on investment (ROI) and a multitude of supplier choices. Current analog and NXDN® digital fleets can share a NEXEDGE® base/repeater station in 12.5 kHz conventional "Mixed Mode," thus providing uninterrupted service as long as needed and a straightforward migration path as aging analog fleets are replaced with digital. Also, NEXEDGE® trunked traffic channels can be shared with existing external analog conventional or trunked logic controllers, extending service to fleets as a transition to NXDN® trunking is underway. Variety of OperationNEXEDGE® systems are configurable in traditional conventional, trunked and wide area trunked network operation modes. IP connectivity for NEXEDGE® trunked sites provides scalability over existing LAN/WAN assets and services. Outstanding Voice QualityThe AMBE+2™ Vocoder is a state-of-the-art voice compression digitization technology that offers superior clarity at varying signal strengths, even at highway speeds.
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