دانلود کتاب Introduction to Digital Professional Mobile Radio
Introduction to Digital Professional Mobile Radio
Professional users of nonpublic mobile radios have seen the public digital cellular networks evolving quickly and successfully, but for their own work they were reluctant to change to digital professional mobile radio (DPMR) even though it has been available since the late 1980s. This reluctance stems from the fact that they depend on their communication tools and they cannot afford for them to fail. This might be why many professionals waited until DPMR technology became commercially feasible and mature enough to perform well even under the worst operational and environmental conditions. However, now that they have been convinced by the public networks that the time for DPMR has come, they want DPMR to be fast, reliable, and cheap. By the way, in the past PMR was the acronym for private mobile radio, but this does not stress clearly enough that professional applications were intended to be the primary application; therefore, professional mobile radio is the better name .
Written by one of the key developers of PMR, this reference provides comprehensive coverage of digital PMR systems, including the standards APCO 25, TETRA and DIIS and the proprietary systems ASTRO, EDACS, iDEN, MOBITEX II and TETRAPOL. Offering insight from the author’s years of experience working with this technology, the book helps you gain a solid understanding of the transition from analogue to digital PMR. It provides you with methods for estimation coverage distance and bandwidth for digital PMR systems. Moreover, the book includes advanced tools which help you solve difficult technical questions in short time with reasonable accuracy. You are provided with a comparison of the properties of conventional analogue and new digital PMR systems to help support the decision to introduce a new radio communication system. This resource features discussions on critical topics, such as transmitter switching spectrum, real Doppler situations and real usable frequency economy. It also discusses alternatives to PMR, such as public cellular systems, and concludes with a look at the future of PMR through the year 2010.
Hans-Peter A. Ketterling