PP Presentation
Radio signals in more detail
There are three regions of the E-M spectrum utilized by these
waves: 902-928 Mhz, 2.4-2.484 Ghz and 5.725-5.850 Ghz.
There are two popular methods of transmitting / receiving
data over a frequency spectrum. These methods were used
by the military in the 1970’s for secure transmission.
FHSS- Frequency hopping spread spectrum involves dividing
a range of radio spectrum into individual channels. The
Transmitter and the reviver follow a predetermined pattern
to hop from one channel to the next to send and receive data.
DSSS- Direct sequence spread spectrum transmissions
occur over a continuos band of frequencies. A unique code
is applied to the input signal, and the receiver uses the same
code to recover the information.