User's Manual

Table Of Contents

Digital Repeater Line

DSP95 Series User’s Guide

Page 15 of 74

WESTELL.COM

25 May 2016 Doc. No. 960-1250-MNL rG

1 Product Overview

1.1 Product Information

Westell Technologies digital repeaters were developed for use within enclosed structures where sufficient signal

strength from local cell sites to operate cell phones is unavailable. Adequate signal strength 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 is typically a directional type, such as a Yagi antenna. Internal antennas are typically

omnidirectional, though

various other types may be used, depending on the coverage application. The Westell DSP

repeater amplifies both the uplink

(phone to tower) and downlink (tower to phone) signals, facilitating

communications to and from the intended wireless infrastructure.

With a maximum total of 90 dB nominal gain on both the uplink and downlink, gain can be adjusted over a range

from 58.5 dB to 90 dB in 0.5 dB steps. Control of the repeater is achieved utilizing a computer connected to a COM

port or via a crossover Ethernet cable connected to the Ethernet port.

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 must change. Configuration parameters are created at the factory and

supplied as files to be downloaded to the repeater. The filter set configurations stored in memory determine the

unit’s adaptability to various field applications. Appendix B describes the band plans and the convention Westell uses

to identify and store the files that make up the filter set. All Westell repeaters are shipped with an active filter set that

is programmed according to customer specifications. In most cases, the installer will not be required to program a

filter.

1.2 Functional Overview

Westell Technologies digital repeaters incorporate the following features for convenient operation, access, protection,

and control:

• Network configuration and control using either a web GUI accessed using a web browser or a menu

driven user interface using the serial port. The GUI does not require Internet access.

• User gain control (affects all passbands)

• Automatic gain control

• Automatic power control

• Overdrive protection (PA limiting)

• Under/Over voltage protection

• Fault protection

• Alarm notification - local/remote