25-08-2017, 09:32 PM
Wireless Transmission Systems
[attachment=27266]
Ground Rules
• NO CHEATING
• Treat this class as your job
– 4 hr credit = 12 hours of work each WEEK
– Prepare for class (read notes and book)
– Turn in assignments on time
– Attend lecture and lab (without attendance, your test grades will
suffer! Not all notes are contained on the slides, new material will
be presented in class)
• Be respectful of your classmates and your instructor
– There are no stupid questions
– Come to class ON TIME, and AWAKE
• Approach this class with the right attitude, don’t take it to
graduate, take it to learn about Wireless communications!
Introduction to Wireless Communications
• What is meant by wireless?
– The physical phenomena known as radio waves were first known
as ‘Hertzian Waves’. Hertz showed that the electro-magnetic
phenomena (under study by Tesla) could be used to transfer energy
between locations without a physical connection.
– Guglielmo Marconi began work in 1894 to reproduce the Hertz
laboratory experiment over greater distances. His study and efforts
brought about the first radio link in the form of wireless telegraph.
His efforts gave him the title: “Father of Radio”
– The combined works of Tesla, Hertz, and Marconi proved that
electro-magnetic phenomena (such as a large spark) generated at
one location could be detected at another location without a direct
physical connection between locations. Thus, the ability to
communicate without wires i.e. ‘Wireless’.
Modulation Overview
Modulation is a process that causes a shift in the range of
frequencies in a signal. Modulation takes a message signal
at baseband and shifts the range of frequencies to achieve
carrier communication.
The term baseband is used to designate the band of
frequencies of the signal delivered by the source or the
input transducer.
The term carrier communication describes the use of a carrier
to shift the frequency range and encode the basband signal
with one or more of the carriers basic parameters:
amplitude, frequency and phase.
Signal Representation
Each modulation technique has inherent strengths and
weaknesses. The following are some items to consider
when choosing a modulation technique.
Amplitude - requires fairly constant receive amplitude for
good performance and usually requires a carrier for phase
estimation. It is very easy to demodulate and works well
for cheap receivers.
Frequency & Phase - modulating in frequency or phase is
relatively the same thing as the two are intricately related.
Requires LTI channel and some indication of the carrier
phase for good performance.
[attachment=27266]
Ground Rules
• NO CHEATING
• Treat this class as your job
– 4 hr credit = 12 hours of work each WEEK
– Prepare for class (read notes and book)
– Turn in assignments on time
– Attend lecture and lab (without attendance, your test grades will
suffer! Not all notes are contained on the slides, new material will
be presented in class)
• Be respectful of your classmates and your instructor
– There are no stupid questions
– Come to class ON TIME, and AWAKE
• Approach this class with the right attitude, don’t take it to
graduate, take it to learn about Wireless communications!
Introduction to Wireless Communications
• What is meant by wireless?
– The physical phenomena known as radio waves were first known
as ‘Hertzian Waves’. Hertz showed that the electro-magnetic
phenomena (under study by Tesla) could be used to transfer energy
between locations without a physical connection.
– Guglielmo Marconi began work in 1894 to reproduce the Hertz
laboratory experiment over greater distances. His study and efforts
brought about the first radio link in the form of wireless telegraph.
His efforts gave him the title: “Father of Radio”
– The combined works of Tesla, Hertz, and Marconi proved that
electro-magnetic phenomena (such as a large spark) generated at
one location could be detected at another location without a direct
physical connection between locations. Thus, the ability to
communicate without wires i.e. ‘Wireless’.
Modulation Overview
Modulation is a process that causes a shift in the range of
frequencies in a signal. Modulation takes a message signal
at baseband and shifts the range of frequencies to achieve
carrier communication.
The term baseband is used to designate the band of
frequencies of the signal delivered by the source or the
input transducer.
The term carrier communication describes the use of a carrier
to shift the frequency range and encode the basband signal
with one or more of the carriers basic parameters:
amplitude, frequency and phase.
Signal Representation
Each modulation technique has inherent strengths and
weaknesses. The following are some items to consider
when choosing a modulation technique.
Amplitude - requires fairly constant receive amplitude for
good performance and usually requires a carrier for phase
estimation. It is very easy to demodulate and works well
for cheap receivers.
Frequency & Phase - modulating in frequency or phase is
relatively the same thing as the two are intricately related.
Requires LTI channel and some indication of the carrier
phase for good performance.