WIT910
1. INTRODUCTION
The WIT910 radio transceiver provides reliable wireless connectivity for either
point-to-point or multipoint applications. Frequency hopping spread spectrum
technology ensures maximum resistance to noise and multipath fading and robustness in
the presence of interfering signals, while operation in the 900MHz ISM band allows
license-free use and worldwide compliance. Standard communication rates between the
WIT910 and the host are supported between 2400bps and 115bps. Non-standard rates
are supported as well. An on-board buffer and an error-correcting over-the-air protocol
provide smooth data flow and simplify the task of integration with existing applications.
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Multipath fading impervious
frequency hopping technology
with 54 frequency channels
(902 to 927 MHz).
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Supports point-to-point or
multipoint applications.
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Meets FCC rules 15.247 for
license-free operation.
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20+ mile range with omni
antenna.
- Transparent
ARQ
protocol
w/512byte buffer ensures data
integrity.
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Digital addressing supports up to
64 networks, with 62 remotes per
network.
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Low power 3.3v CMOS signals
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Selectable 10mW, 100mW or
500mW transmit power.
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Built-in data scrambling reduces
possibility of eavesdropping.
- Nonvolatile
memory
stores
configuration when powered off.
-
Smart power management features
for low current consumption.
-
Dynamic TDMA slot assignment
that maximizes throughput.
-
Simple serial interface handles both
data and control at up to 115.2 bps.
1.1 Why Spread Spectrum?
The radio transmission channel is very hostile, corrupted by noise, path loss and
interfering transmissions from other radios. Even in a pure interference-free
environment, radio performance faces serious degradation through a phenomenon
known as multipath fading. Multipath fading results when two or more reflected
rays of the transmitted signal arrive at the receiving antenna with opposing phase,
thereby partially or completely canceling the desired signal. This is a problem
particularly prevalent in indoor installations. In the frequency domain, a multipath
fade can be described as a frequency-selective notch that
shifts in location and
intensity over time as reflections change due to motion of the radio or objects within
its range. At any given time, multipath fades will typically occupy 1% - 2% of the
band. This means that from a probabilistic viewpoint, a conventional radio system
faces a 1% - 2% chance of signal impairment at any given time due to multipath.
©2010-2015 by Murata Electronics N.A., Inc.
WIT910 Integration guide (R) 05/14/15
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