CSI CSI-DSP85-250-AW Скачать руководство пользователя страница 5

Страница: 5 / 40

- 5 -

Product Introduction

Cellular Specialties, Inc. (CSI) developed this digital repeater for use within enclosed structures where
sufficient signal from local cell sites to operate wireless phones is unavailable. Adequate signal must be
available outside the structure as a prerequisite to achieving in-building coverage. The Digital Repeater is
connected to an external antenna, usually on the roof, and to one or more internal antennas placed
strategically throughout the area where wireless service is desired.

The external antenna typically is directional, such as a “yagi”. Internal antennas are typically omnidirec-
tional, although various other types may be used depending on the coverage application. The repeater
amplifies both the “uplink”(phone to tower) & “downlink”(tower to phone) signals thus facilitating
communications to and from the intended wireless infrastructure.

With a maximum total of

+85

dB nominal gain on both the up and down links, gain can be adjusted over a

range from +53.5dB to +85dB in 0.5dB steps. Control of the repeater is achieved utilizing a computer
connected to comm. port 1 or 2 or via a Crossover Ethernet cable connected to the Ethernet port. There
are also an LED indicator indicate ALARM status.

A specific filtering process modifies each amplification chain. This process digitally converts the assigned
spectrum and then applies digital signal processing (DSP) techniques. DSP is used to create passbands
that selects the RF energy passing through either the uplink or downlink paths. After the digital processing
is complete, the information is converted back to an analog signal that is applied to the remaining stages
of amplification. The resulting signals emitted by the repeater are specific to the network service providers’
requirements. If these requirements change, only the DSP configuration parameters need change in order
to adapt. Configuration parameters are created at the factory and supplied as files that may be down-
loaded to the repeater. The filter set configurations stored in memory determine the unit’s adaptability to
various field applications. The following pages describe the PCS band plan as well as the convention CSI
uses to identify and store the files that make up the filter set. All units are shipped with an active filter set
that is programmed according to the ordering parties’ specifications. In most cases, the installer will not
have to program a filter.

Important Safety Information

Antennas used for the purpose of radiating signals indoors are limited to a

maximum

gain of 3 dBi. The outdoor antenna used for the

purpose of communicating to the wireless infrastructure is limited to 14dBi gain, or any combination of gain and loss that equates to
14dB at input. Each antenna must be positioned to observe minimum separation requirements from all users and bystanders. The
following guidelines should be used when considering separation distances.

INDOOR

antennas must be placed such that, under normal conditions, personnel cannot come within 20 cm (~8.0 in.) from any inside

antenna. Adhering to this minimum separation will ensure that the employee or bystander cannot exceed RF exposures beyond the
maximum permissible limit as defined by section 1.1310 i.e. limits for General Population/Uncontrolled Exposure.

OUTDOOR

antenna

must be positioned such that, under normal conditions, personnel cannot approach closer than 183 cm. (~6 ft.). A

directional antenna having a maximum gain of 14 dBi is used, precautions should be taken to prevent personnel from routinely passing
through the main radiation beam at a distance closer than specified.

Terms Used in This Manual

AGC

= Automatic Gain Control

ERP

= Effective Radiated Power

APC

= Automatic Power Control

FCS

= Feedback Cancellation System

AUI

= Attachment Unit Interface

FPGA