23-04-2012, 03:03 PM
HEAD MOVEMENT BASED VOICE ENABLED WIRELESS SWITCHING FOR PHYSICALLY CHALLENGED
[attachment=20626]
TRANSMITTER/ RECEIVER DESIGN, DEVELOPMENT AND INTEGRATION
Modulation is the process of varying a carrier signal in order to use that signal to convey information.
The three key parameters of a sine wave are its amplitude, its phase and its frequency, all of which can be modified in accordance with an information signal to obtain the modulated signal.
There are several reasons to modulate a signal before transmission in a medium. These include the ability of different users sharing a medium (multiple access), and making the signal properties physically compatible with the propagation medium.
RF TRANSMITTER
The RF transmitter used in our project is TWS-434A. This RF transmitter transmits data in the frequency range of 433.92 MHz with a range of approximately 400 foot (open area) outdoors.
Indoors, the range is approximately 200 foot, and will go through most walls. TWS-434A has features which includes small in size, low power consumption i.e. 8mW and operate from 1.5 to 12 Volts-DC, excellent for applications requiring short-range RF signal.
RF RECEIVER
Data to be send is Amplitude modulation with the carrier RF signal.
The RF receiver receives an RF signal, converts the RF signal to an IF signal, and then converts the IF signal to a base band signal, which it then provides to the base band processor.
As is also known, RF transceivers typically include sensitive components susceptible to noise and interference with one another and with external sources.
[attachment=20626]
TRANSMITTER/ RECEIVER DESIGN, DEVELOPMENT AND INTEGRATION
Modulation is the process of varying a carrier signal in order to use that signal to convey information.
The three key parameters of a sine wave are its amplitude, its phase and its frequency, all of which can be modified in accordance with an information signal to obtain the modulated signal.
There are several reasons to modulate a signal before transmission in a medium. These include the ability of different users sharing a medium (multiple access), and making the signal properties physically compatible with the propagation medium.
RF TRANSMITTER
The RF transmitter used in our project is TWS-434A. This RF transmitter transmits data in the frequency range of 433.92 MHz with a range of approximately 400 foot (open area) outdoors.
Indoors, the range is approximately 200 foot, and will go through most walls. TWS-434A has features which includes small in size, low power consumption i.e. 8mW and operate from 1.5 to 12 Volts-DC, excellent for applications requiring short-range RF signal.
RF RECEIVER
Data to be send is Amplitude modulation with the carrier RF signal.
The RF receiver receives an RF signal, converts the RF signal to an IF signal, and then converts the IF signal to a base band signal, which it then provides to the base band processor.
As is also known, RF transceivers typically include sensitive components susceptible to noise and interference with one another and with external sources.