# 3.20 Analog signal processing problems  (Page 3/6)

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## Power transmission

The network shown in the figure represents a simple power transmission system. The generator produces 60 Hz and is modeled by a simple Thévenin equivalent.The transmission line consists of a long length of copper wire and can be accurately described as a 50Ω resistor.

1. Determine the load current ${R}_{\text{L}}$ and the average power the generator must produce so that the load receives 1,000 watts of average power. Why does the generator need to generate more than 1,000 watts of average power to meet this requirement?
2. Suppose the load is changed to that shown in the second figure . Now how much power must the generator produce to meet the same power requirement?Why is it more than it had to produce to meet the requirement for the resistive load?
3. The load can be compensated to have a unity power factor (see exercise ) so that the voltage and current are in phase for maximum power efficiency. The compensation technique is to place a circuit in parallel to the load circuit. What element works and what is its value?
4. With this compensated circuit, how much power must the generator produce to deliver 1,000  average power to the load?

## Optimal power transmission

The following figure shows a general model for power transmission. The power generator is represented by a Thévinin equivalent and the load by a simple impedance.In most applications, the source components are fixed while there is some latitude in choosing the load.

1. Suppose we wanted the maximize "voltage transmission:" make the voltage across the load as large as possible.What choice of load impedance creates the largest load voltage? What is the largest load voltage?
2. If we wanted the maximum current to pass through the load, what would we choose the load impedance to be? What is this largest current?
3. What choice for the load impedance maximizes the average power dissipated in the load? What is most power the generator can deliver?
One way to maximize a function of a complex variable is to write the expression in terms of the variable's real and imaginary parts, evaluate derivatives with respect to each, set both derivatives to zero and solve the two equations simultaneously.

## Big is beautiful

Sammy wants to choose speakers that produce very loud music. He has an amplifier and notices that the speaker terminals are labeled" $8\Omega$ source."

1. What does this mean in terms of the amplifier's equivalent circuit?
2. Any speaker Sammy attaches to the terminals can be well-modeled as a resistor. Choosing a speaker amounts to choosing the values for the resistor.What choice would maximize the voltage across the speakers?
3. Sammy decides that maximizing the power delivered to the speaker might be a better choice. What values for the speaker resistor should be chosen to maximize the power delivered to the speaker?

## Sharing a channel

Two transmitter-receiver pairs want to share the same digital communications channel. The transmitter signalswill be added together by the channel. Receiver design is greatly simplified if first we remove the unwantedtransmission (as much as possible). Each transmitter signal has the form $\forall t, 0\le t\le T\colon {x}_{i}(t)=A\sin (2\pi {f}_{i}t)$ where the amplitude is either zero or $A$ and each transmitter uses its own frequency ${f}_{i}$ . Each frequency is harmonically related to the bitinterval duration $T$ , where the transmitter 1 uses the the frequency $\frac{1}{T}$ . The datarate is 10Mbps.

1. Draw a block diagram that expresses this communication scenario.
2. Find circuits that the receivers could employ to separate unwanted transmissions. Assume the receivedsignal is a voltage and the output is to be a voltage as well.
3. Find the second transmitter's frequency so that the receivers can suppress the unwanted transmission byat least a factor of ten.

what is Nano technology ?
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
why we need to study biomolecules, molecular biology in nanotechnology?
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
why?
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
what does nano mean?
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
absolutely yes
Daniel
how to know photocatalytic properties of tio2 nanoparticles...what to do now
it is a goid question and i want to know the answer as well
Maciej
Abigail
for teaching engĺish at school how nano technology help us
Anassong
Do somebody tell me a best nano engineering book for beginners?
there is no specific books for beginners but there is book called principle of nanotechnology
NANO
what is fullerene does it is used to make bukky balls
are you nano engineer ?
s.
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
Tarell
what is the actual application of fullerenes nowadays?
Damian
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
Tarell
what is the Synthesis, properties,and applications of carbon nano chemistry
Mostly, they use nano carbon for electronics and for materials to be strengthened.
Virgil
is Bucky paper clear?
CYNTHIA
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
NANO
so some one know about replacing silicon atom with phosphorous in semiconductors device?
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Harper
Do you know which machine is used to that process?
s.
how to fabricate graphene ink ?
for screen printed electrodes ?
SUYASH
What is lattice structure?
of graphene you mean?
Ebrahim
or in general
Ebrahim
in general
s.
Graphene has a hexagonal structure
tahir
On having this app for quite a bit time, Haven't realised there's a chat room in it.
Cied
how did you get the value of 2000N.What calculations are needed to arrive at it
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