Fouriers derivation of the ct fourier transform x(t)-an aperiodic signal view it as the limit of a periodic signal as t→∞ For a periodic signal the harmonic components are spaced Oo=2π/ T apart. AsT→∞,Obo→>0, and harmonic components are space

Another(important! ) example: Periodic Impulse train n(t)=∑(t Sampling function important for sampling .2T

Representation of ct signals Approximate any input x(t) as a sum of shifted, scaled

Portrait of Jean Baptiste Joseph Fourier Image removed due to copyright considerations Signals& Systems, 2nd ed. Upper Saddle River, N.J. Prentice Hall, 1997, p 179

1Some examples of systems 2 System properties and examples CAusality

Question: Are there sets of basic\ signals so that a) We can represent rich classes of signals as linear combinations of these building block signals b) The response of ltI Systems to these basic signals are both simp and insightful Fact: For LtI Systems(CT or dt) there are two natural choices for these building blocks Focus for now:

Can be continuous Trajectory of a space shuttle Mass density in a cross-section of a brain · Can be discrete dNa base sequence Digital image pixels Can be 1-D,2-D,·N-D For this course: Focus on a single(1-D) independent variable which we call“time

一、嵌入式系统的结构 二、DSP的发展历史和特点 三、DSP系统的设计 四、C6000DSP的CPU和存储器 五、DSP的中断使用 六、DSP的时钟 七、信号线的布置

第一部分选择题(共30分) 一、单项选择题(本大题共10小题,每小题3分,共30分) 在每小题列出的四个选项中只有一个是符合题目要求的.请将其代码填在题后的括号内。错选或未选均无分。 串联谐振电路,固有谐振频率取决于 A电源电压幅值 B电源电压的初始相位 C.电源电压频率

3.1 X(eo)=2xnJe-jon where x[n] is a real sequence. Therefore X(e)=Rl∑xnlo/。 ∑xR(-mu)=∑ x[n]cos(on),and xmm)=m∑刈nm∑刈mc-m)=-2 xn] sin(oon) Since cos(on)and sin(on)are, respectively, even and odd functions of o, Xre(eJo) is an even function of o