%========================開始提取加噪信號的各類特征值================================
for n=1:1:50;
m=n*Ns;
x=(n-1)*Ns;
for i=x+1:m; %提取加噪信號'signal_with_noise=y+noise'的前256個元素，抽取50次
y0(i)=signal_with_noise(i);
end
Y=fft(y0); %對調(diào)制信號進(jìn)行快速傅里葉算法（離散）
y1=hilbert(y0) ; %調(diào)制信號實(shí)部的解析式
factor=0; %開始求零中心歸一化瞬時幅度譜密度的最大值gamma_max
for i=x+1:m;
factor=factor+y0(i);
end
ms=factor/(m-x);
an_i=y0./ms;
acn_i=an_i-1;
end
gamma_max=max(fft(acn_i.*acn_i))/Ns
%========================開始提取加噪信號的各類特征值================================
for n=1:1:50;
m=n*Ns;
x=(n-1)*Ns;
for i=x+1:m; %提取加噪信號'signal_with_noise=y+noise'的前256個元素，抽取50次
y0(i)=signal_with_noise(i);
end
Y=fft(y0); %對調(diào)制信號進(jìn)行快速傅里葉算法（離散）
y1=hilbert(y0) ; %調(diào)制信號實(shí)部的解析式
factor=0; %開始求零中心歸一化瞬時幅度譜密度的最大值gamma_max
for i=x+1:m;
factor=factor+y0(i);
end
ms=factor/(m-x);
an_i=y0./ms;
acn_i=an_i-1;
end
gamma_max=max(fft(acn_i.*acn_i))/Ns
The capability of radio waves to provide almost instantaneous distant communications
without interconnecting wires was a major factor in the explosive growth of communica-
tions during the 20th century. With the dawn of the 21st century, the future for communi-
cations systems seems limitless. The invention of the vacuum tube made radio a practical
and affordable communications medium.
The continued reduction of integrated circuit feature sizes and
commensurate improvements in device performance are fueling the progress
to higher functionality and new application areas. For example, over the last
15 years, the performance of microprocessors has increased 1000 times.
Analog circuit performance has also improved, albeit at a slower pace. For
example, over the same period the speed/resolution figure-of-merit of
analog-to-digital converters improved by only a factor 10.
At the macroscopic level of system layout, the most important issue is path loss. In the
older mobile radio systems that are limited by receiver noise, path loss determines SNR and
the maximum coverage area. In cellular systems, where the limiting factor is cochannel
interference, path loss determines the degree to which transmitters in different cells interfere
with each other, and therefore the minimum separation before channels can be reused.
Soon after Samuel Morse’s telegraphing device led to a deployed electri-
cal telecommunications system in 1843, waiting lines began to form by those
wanting to use the system. At this writing queueing is still a significant factor in
designing and operating communications services, whether they are provided
over the Internet or by other means, such as circuit switched networks.
The need to develop reliable microelectronic devices capable of operating at high
speeds with complex functionality requires a better understanding of the factors
that govern the thermal performance of electronics. With an increased demand
on system reliability and performance combined with miniaturization of the
devices, thermal consideration has become a crucial factor in the design of elec-
tronic packages, from chip to system levels.
Electrostatic discharge (ESD) events can have serious detrimental
effects on the manufacture and performance of microelectronic devices,
the systems that contain them, and the manufacturing facilities used to
produce them. Submicron device technologies, high system operating
speeds, and factory automation are making ESD control programs a
critical factor in the quality and reliability of ESD-sensitive products.
ESD is a crucial factor for integrated circuits and influences their quality and reliability.
Today increasingly sensitive processes with deep sub micron structures are developed. The
integration of more and more functionality on a single chip and saving of chip area is
required. Integrated circuits become more susceptible to ESD/EOS related damages.
However, the requirements on ESD robustness especially for automotive applications are
increasing. ESD failures are very often the reason for redesigns. Much research has been
conducted by semiconductor manufacturers on ESD robust design.
In the present era, low observability is one of the critical requirements in aerospace
sector, especially related to defense. The stealth technology essentially relates to
shaping and usage of radar absorbing materials (RAM) or radar absorbing struc-
tures (RAS). The performance of such radar cross section (RCS) reduction tech-
niques is limited by the bandwidth constraints, payload requirements, and other
structural issues. Moreover, with advancement of materials science, the structure
geometry no longer remains key decisive factor toward stealth.
