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Showing 1 to 13 of 13 for “"land mobile radio"”.
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Noise blanker for land mobile radio systems
The field of private mobile radio systems (taxis, police, emergency services, dispatch systems etc.) is undergoing accelerated change and deregulation. More users, demanding more services with better quality, are squeezed into the same bandwidth. However, noise and impulsive noise levels on the …
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Security in Packet-Switched Land Mobile Radio Backbone Networks
… lower-cost technology and services, many land mobile radio (LMR) operators have begun transitioning from circuit-switched to packet-switched backbone networks to handle their future communication needs. Due to the unique demands of packet-switched backbone networks for LMR, it may not be …
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Design Considerations in a Modern Land Mobile Radio System
Modern Land Mobile Radio has the potential for large growth in the near future. Current regulations have set the stage for a required transition to more spectrally efficient technologies. While several organizations are working to ease this transition, there still remain many details and feature …
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A land mobile radio coverage area prediction model for New Zealand
… initial step in the development of a nationwide land mobile coverage area prediction model for New Zealand. The most suitable approach is shown to be a computer-based method which includes corrections for both environmental and terrain features. Extensive field trials performed in Auckland at 76 …
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Performance of GMSK and 7/4-DQPSK Modulations in Land Mobile Radio Channels
… that provide telephone communication service to mobile users have experienced a rapid growth during the last five years. The current cellular systems are analog in nature. These systems employ frequency modulation. As the spectrum gets crowded, bandwidth efficient digital systems will find …
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Investigation of a Packet-Switched Inter-System Interface for Land Mobile Radio Systems
Traditionally, and up to this date, Land Mobile Radio (LMR) systems have been interconnected via leased lines and microwave links across circuit-switched networks. With the recent deployment of digital LMR standards such as the Association of Public and Communications Officials (APCO) Project 25 …
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Impact of Queuing Schemes and VPN on the Performance of a Land Mobile Radio VoIP System
Land mobile radio (LMR) systems are used for communication by public safety and other government and commercial organizations. LMR systems offer mission-critical or even life-critical service in the day-to-day activities of such organizations. Traditionally, a variety of different LMR systems have …
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Fade durations in satellite-path mobile radio propagation
Fades on satellite to land mobile radio links are caused by several factors, the most important of which are multipath propagation and vegetative shadowing. Designers of vehicular satellite communications systems require information about the statistics of fade durations in order to overcome or …
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Measurement of Antenna Performance in Analog LMR Systems Using PL Tone Analysis
… the in situ antenna performance in analog land mobile radio (LMR) FM systems. The gain (efficiency and directivity) and self-impedance of an antenna sufficiently characterize its performance and a number of traditional methods exist to measure these quantities. However it is hard to do …
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Transmission of data under multipath transmission conditions
… channels. Because of this, data communication to mobile vehicles is increasing rapidly. In addition, data communication is seen as a method of relieving the current congestion of mobile radio telephone bands in the U.K. Highly reliable data communication over mobile radio channels is particularly …
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A discrete RET Model for Micro- and Millimetre Wave Propagation through Vegetation
… design and implementation on the availability of radiowave propagation models. In the particular case of land mobile radio systems and wireless fixed access systems, obstacles in the form of vegetation volumes, e.g formations of trees, are likely to influence radio propagation, giving rise to …
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Wideband RF Front End Daughterboard Based on the Motorola RFIC
The goal of software-defined radio (SDR) is to move the processing of radio signals from the analog domain to the digital domain — to use digital microchips instead of analog circuit components. Until faster, higher-precision analog-to-digital (ADCs) and digital-to-analog converters (DACs) become …
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Communication technologies and data processing for safety
… we have developed a indoor navigation system for mobile devices. The application is able to follow the user and it indicates the shortest path to achieve a specific destination. It uses only smartphone motion sensor and not requires the use of extra equipment. Moreover, thanks to an algorithm …