The
rms (root-mean-square) value of
a periodic signal is defined to be
$$s=\sqrt{\frac{1}{T}\int_{0}^{T} s(t)^{2}\,d t}$$ where
$T$ is defined to be the signal's
period :
the smallest positive number such that
$s(t)=s(t+T)$ .
What is the period of
$s(t)=A\sin (2\pi {f}_{0}t+\phi )$ ?
What is the rms value of this signal? How is it
related to the peak value?
What is the period and rms value of the
depictedsquare wave , generically denoted
by
$\mathrm{sq}(t)$ ?
By inspecting any device you plug into a wall socket,
you'll see that it is labeled "110 volts AC". What isthe expression for the voltage provided by a wall
socket? What is its rms value?
Modems
The word "modem" is short for "modulator-demodulator."
Modems are used not only for connecting computers totelephone lines, but also for connecting digital
(discrete-valued) sources to generic channels. In thisproblem, we explore a simple kind of modem, in which
binary information is represented by the presence orabsence of a sinusoid (presence representing a "1" and
absence a "0"). Consequently, the modem's transmittedsignal that represents a single bit has the form
$$x(t)=A\sin (2\pi {f}_{0}t)\text{,}0\le t\le T$$ Within each bit interval
$T$ , the amplitude is either
$A$ or zero.
What is the smallest transmission interval that
makes sense with the frequency
${f}_{0}$ ?
Assuming that ten cycles of the sinusoid comprise a
single bit's transmission interval, what is thedatarate of this transmission scheme?
Now suppose instead of using "on-off" signaling, we
allow one of several
different values for the amplitude during any transmission
interval. If
$N$ amplitude values are used, what is the resulting
datarate?
The classic communications block diagram applies to
the modem. Discuss how the transmitter mustinterface with the message source since the source
is producing letters of the alphabet, not bits.
Advanced modems
To transmit symbols, such as letters of the alphabet, RUcomputer modems use two frequencies (1600 and 1800 Hz)
and several amplitude levels. A transmission is sentfor a period of time
$T$ (known as the transmission or baud interval) and equals
the sum of two amplitude-weighted carriers.
$$x(t)={A}_{1}\sin (2\pi {f}_{1}t)+{A}_{2}\sin (2\pi {f}_{2}t)\text{,}0\le t\le T$$ We send successive symbols by choosing an appropriate
frequency and amplitude combination, and sending themone after another.
What is the smallest transmission interval that
makes sense to use with the frequencies given above?In other words, what should
$T$ be so that an
integer number of cycles of the carrier occurs?
Sketch (using Matlab) the signal that modem produces
over several transmission intervals. Make sure youaxes are labeled.
Using your signal transmission interval, how many
amplitude levels are needed to transmit ASCIIcharacters at a datarate of 3,200 bits/s? Assume use
of the extended (8-bit) ASCII code.
We use a discrete set of values for
${A}_{1}$ and
${A}_{2}$ .
If we have
${N}_{1}$ values for amplitude
${A}_{1}$ ,
and
${N}_{2}$ values for
${A}_{2}$ ,
we have
${N}_{1}{N}_{2}$ possible symbols that can be sent during each
$T$ second interval. To
convert this number into bits (the fundamental unit ofinformation engineers use to qualify things), compute
$\log_{2}({N}_{1}{N}_{2})$ .
Questions & Answers
where we get a research paper on Nano chemistry....?
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest.
Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.?
How this robot is carried to required site of body cell.?
what will be the carrier material and how can be detected that correct delivery of drug is done
Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
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?