Status WRX900 Series, Руководство по эксплуатации

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3 Basics
3.1 Radio technology
The characteristic framework conditions for each transmission system include the
available band width in the electro-magnetic spectrum and the maximum
permissible transmission capacity. These parameters define the channel capacity.
The main selection criteria for the frequency range to be used include the
requirement of a long range, interference resistance as well as the possibility to
be able to apply a customized transmission protocol in public spectrum band. The
focus when selecting the possible communication technologies is placed on
miniaturizing the transmitting and receiving circuit as well as the power
consumption, on enhancing the transmission safety and the transmission stability
as well as on saving costs of the technology involved. The use of a wireless
connection generates above all lower costs, higher flexibility and mobility as well
as simpler handling.
Taking the currently valid legislation into account and by complying with the
available norms and industrial standards, we have opted in favor of a wireless
solution for the application of the WRX900 system without a generally specified
protocol in the ISM band on the following frequencies: 868.4MHz (Europe)
Regarding the ISM band, in certain areas there are stringent regulations in place
concerning duty cycle, channel distribution as well as transmission capacity. The
various subdivisions within this frequency band are shown on the following figure
1.
Figure 1: Subdivision of the 868 MHz frequency band
The ERP power value (ERP: equivalent radiated power) value represents the
permitted transmission capacity related to a Lambda/2 dipole gain. When
utilizing the duty cycle, during the transmission pulse at a very small pulse width,