1 1 Signals and systems Faculty of Electronics, Telecommunications and Information Technologies Communications Department http://shannon.etc.upt.ro/teaching/ss-pi All universities from Romania want to be among the 500 top universities 2 QS ranking for year 2019: https://www.topuniversities.com/universit y-rankings/world-university- rankings/2019 This is just one ranking …
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Signals and systemsSignals and systems Faculty of Electronics, Telecommunications and Information Technologies Communications Department ... Alan V. Oppenheim, Alan S. Willsky with
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Signals and systems
Faculty of Electronics, Telecommunications and Information
Cost reduction has favoured equipping cars with radar
sensors to prevent accidents.
But this involves signal processing of advanced level
and solving estimation and detection problems.
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Car with radar sensors of 24GHz & 77 GHz
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Architecture of frequency-modulated continuous wave (FMCW)
radar. Two antennas are used: transmit and receive. The received
signal is multiplied by the emitted signal, obtaining signals with
beat frequencies given by the Doppler effect (corresponding to
each target). After sampling and A/D conversion, frequency
analysis is performed, using the FFT algorithm.
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Commonly used FMCW signals are chirp like. The
instantaneous frequency varies linearly in time
(increasing or decreasing)
Time representation of
chirp signal Instantaneous frequency of
chirp signals
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We can use rapid chirp of duration up to 100 microsec. The beat
frequency is
2v 2 2SW SWB
CPI CPI
B R B Rf
cT cT
2R 2v 2vexp 2 ; m=0, 1, ... ,M-1
c cch ch chy mT a mT j mT
exp 2 Tx t a t j f t
If the emitted signal is
then the received signal is
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A double frequency analysis, using the FFT algorithm, leads to the
estimation of the range R and velocity, v of the target
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Speed (m/s)
Range (
mete
rs)
Range-Speed Response Pattern
-200 -100 0 100 2000
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40
60
80
100
120
140
160
180
200
Pow
er
(dB
)
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
Here is an example with 9 detected targets at different ranges
having different velocities
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COURSE OBJECTIVES
This course is found in electrical and computer engineering curricula, the concepts and techniques that form the core of the subject are of fundamental importance in all engineering disciplines.
Our approach has been guided by the continuing developments in technologies for signal and system design and implementation, which made it increasingly important for a student to have equal familiarity with techniques suitable for analyzing and synthesizing both continuous-time and discrete-time systems.
Significant emphasis will be placed both
on time domain analysis of systems through the operation of convolution
and
on frequency domain analysis of systems using the Fourier transforms.