User Manual

Page 3
1. General Product Description
SMART Amplifier (SMARTAMP) is a new bi-directional antenna-
mount amplifier designed to match any advanced spread
spectrum system, either direct sequence or frequency
hopping, to allow the extension of the operating range in
wireless environment. It is provided in a wide range of
frequencies, such as 900 MHz, 2400 MHz, or 5800 MHz where
advanced spread spectrum systems are operated. It works in
Time-Division Duplex (TDD) mode that allows the radio device
sharing the antenna in different time intervals. SMARTAMP
consists of an intelligent algorithm and Automatic Gain
Controlled (AGC) circuits to maintain the output power and
prevent transmit signal saturation. The input transmit power
level is sensed by the Radio Frequency (RF) sensor and the
gain is automatically adjusted to minimize the signal
distortion so that the desired signal quality can be
assured.
This product has a wide range of wireless applications in
Wireless Local Area Network (WLAN), Wireless Local Loop
(WLL), Wireless Internet Access (WIA), wireless modem
connection with point-to-point, point-to-multipoint, where
the Time Division Duplex (TDD) technology is used.
2. Background
In wireless applications, when longer operating range is
required, the add-on antenna amplifier and DC injector set
are often a choice. Because of different site layout and
hardware configuration, it is almost impossible for
amplifier manufacture to design the amplifier and fit all
applications. Typically, in most applications, the
interconnection cable could have different length from a few
feet to a few hundred feet. The attenuation between DC
injector and bi-directional amplifier could be few dB to
more than 20 dB. Also, different radio modems have different
output powers. Thus, the system installer must carefully
measure the input RF power at the antenna amplifier and
specify the gain of the amplifier in order to maintain the
system performance. With different systems, different
amplifiers are required. With this invention, the major
difference as compared to other existing technology, is the
‘‘SMART function’’ - power level detection and automatic
gain control circuit. With SmartAmp, the gain can be
intelligently adapt to the input power level in a wide range
and automatically further adjusted to accommodate the cable
and connectors loss, by however length and configuration.
The output power level is monitored and maintained
intelligently, hence the desired performance can be achieved
in all hardware configurations for TDD wireless applications
irrespective of installation environment.
The table below summarizes the difference between SMARTAMP
and other TDD antenna-mount amplifier product.