RU Electronics has been contracted to design a Doppler radar system.
Radar transmitters emit a signal that bounces off any conducting object.Signal differences between what is sent and the radar return is processed and features of interest extracted.
In
Doppler systems, the object's speed along the direction of the radar beam is the feature the design must extract.
The transmitted signal is a sinsusoid:
.
The measured return signal equals
, where the Doppler offset frequency
equals
, where
is the car's velocity coming toward the transmitter.
Design a system that uses the transmitted and return signals as inputs and produces
.
One problem with designs based on overly simplistic design goals is that they are sensitive to unmodeled assumptions.
How would you change your design, if at all, so that whether the car is going away or toward the transmitter could be determined?
Suppose two objects traveling different speeds provide returns.
How would you change your design, if at all, to accomodate multiple returns?
Demodulating an am signal
Let
denote the signal that has been amplitude modulated.
Radio stations try to restrict the amplitude of thesignal
so that it is less than one in magnitude. The frequency
is very large compared to the frequency content of the
signal. What we are concerned about here is nottransmission, but reception.
The so-called coherent demodulator simply multiplies
the signal
by a sinusoid having the same frequency as thecarrier and lowpass filters the result. Analyze
this receiver and show that it works. Assume thelowpass filter is ideal.
One issue in coherent reception is the phase of the
sinusoid used by the receiver relative to that usedby the transmitter. Assuming that the sinusoid of
the receiver has a phase
, how does the
output depend on
? What is the
worst possible value for this phase?
The incoherent receiver is more commonly used
because of the phase sensitivity problem inherent incoherent reception. Here, the receiver full-wave
rectifies the received signal and lowpass filtersthe result (again ideally). Analyze this receiver.
Does its output differ from that of the coherentreceiver in a significant way?
Unusual amplitude modulation
We want to send a band-limited signal having the
depicted spectrum with amplitude modulation in the usual way.
I.B. Different suggests using the square-wave carrier shown
below .
Well, it is different, but his friends wonder if any technique can demodulate it.
Find an expression for
, the Fourier transform of the modulated signal.
Sketch the magnitude of
, being careful to label important magnitudes and frequencies.
What demodulation technique obviously works?
I.B. challenges three of his friends to demodulate
some other way.
One friend suggests modulating
with
, another wants to try modulating with
and the third thinks
will work.
Sketch the magnitude of the Fourier transform of the signal each student's approach produces.Which student comes closest to recovering the original signal?
Why?
Questions & Answers
Three charges q_{1}=+3\mu C, q_{2}=+6\mu C and q_{3}=+8\mu C are located at (2,0)m (0,0)m and (0,3) coordinates respectively. Find the magnitude and direction acted upon q_{2} by the two other charges.Draw the correct graphical illustration of the problem above showing the direction of all forces.
To solve this problem, we need to first find the net force acting on charge q_{2}. The magnitude of the force exerted by q_{1} on q_{2} is given by F=\frac{kq_{1}q_{2}}{r^{2}} where k is the Coulomb constant, q_{1} and q_{2} are the charges of the particles, and r is the distance between them.
Muhammed
What is the direction and net electric force on q_{1}= 5µC located at (0,4)r due to charges q_{2}=7mu located at (0,0)m and q_{3}=3\mu C located at (4,0)m?
Capacitor is a separation of opposite charges using an insulator of very small dimension between them. Capacitor is used for allowing an AC (alternating current) to pass while a DC (direct current) is blocked.
Gautam
A motor travelling at 72km/m on sighting a stop sign applying the breaks such that under constant deaccelerate in the meters of 50 metres what is the magnitude of the accelerate
velocity can be 72 km/h in question. 72 km/h=20 m/s, v^2=2.a.x , 20^2=2.a.50, a=4 m/s^2.
Mehmet
A boat travels due east at a speed of 40meter per seconds across a river flowing due south at 30meter per seconds. what is the resultant speed of the boat
which has a higher temperature, 1cup of boiling water or 1teapot of boiling water which can transfer more heat 1cup of boiling water or 1 teapot of boiling water explain your . answer
I believe temperature being an intensive property does not change for any amount of boiling water whereas heat being an extensive property changes with amount/size of the system.
Someone
Scratch that
Someone
temperature for any amount of water to boil at ntp is 100⁰C (it is a state function and and intensive property) and it depends both will give same amount of heat because the surface available for heat transfer is greater in case of the kettle as well as the heat stored in it but if you talk.....
Someone
about the amount of heat stored in the system then in that case since the mass of water in the kettle is greater so more energy is required to raise the temperature b/c more molecules of water are present in the kettle
pratica A on solution of hydro chloric acid,B is a solution containing 0.5000 mole ofsodium chlorid per dm³,put A in the burret and titrate 20.00 or 25.00cm³ portion of B using melting orange as the indicator. record the deside of your burret tabulate the burret reading and calculate the average volume of acid used?
No. According to Isac Newtons law. this two bodies maybe you and the wall beside you.
Attracting depends on the mass och each body and distance between them.
Dlovan
Are you really asking if two bodies have to be charged to be influenced by Coulombs Law?
Specific heat capacity is a measure of the amount of energy required to raise the temperature of a substance by one degree Celsius (or Kelvin). It is measured in Joules per kilogram per degree Celsius (J/kg°C).
AI-Robot
specific heat capacity is the amount of energy needed to raise the temperature of a substance by one degree Celsius or kelvin
ROKEEB
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