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Appendix B: About Digital Wireless Technology
Appendix B: About Digital Wireless Technology
The Digital Wireless signal transmission type used by the Lorex LW2201 series is also known as
FHSS –
Frequency Hopping Spread
Spectrum. This type of signal is highly resistant to deliberate jamming as it
generates a channel hopping sequence using an algorithm generated by the receiver system.
The 2.4GHz (2.400-2.480Ghz) band is being divided into sections or paths of 2MHz per section, and each
second the transmission signal hops hundreds of times in a specified sequence within this frequency
range. The overall bandwidth required for frequency hopping is much wider then 2MHz however because
transmission occurs only on a small section of this bandwidth at any given time, the signal being
transmitted does not suffer from greatly reduced signal degradation and also avoids blocked paths other
devices who act as sources of competing signals. The strength of the signal being transmitted is set to be
from 13.5-16dBm, which is much higher then the analog transmission signal allowed by authorities
around the Globe.
When an image is captured by the camera it is instantly converted from an analog to digital signal and
packaged into small packets. With each successful transmission via the 2 MHz paths discussed above,
the packets of information containing images are delivered to the receiver and decoded into analog
information. The information can then be displayed on devices that are connected to the wireless receiver
(RX).
A device pairing process is required to synchronize the transmitter (TX, Camera) and the receiver (RX).
This allows the transmitter and receiver to be on the same frequency and use the same algorithm for
frequency hopping. This ensures that only the paired transmitter and receiver can maintain
communication signal by hopping to the same frequency paths at the exact same time. As a result, the
chance that other devices within the same frequency range are on the same frequency, at the same time
and in the same order is extremely unlikely. Note that the pairing process is already done at the factory
for products that ship within the same packaging. Only when add-on devices are purchased is a pairing
process required.
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