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Appendix B: About Digital Wireless Technology
Appendix B: About Digital Wireless Technology
The Digital Wireless signal transmission type used by receiver 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 frequen
cy 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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