一段关于matlab的英文求操作帮助要做matlab的实验,明天写.下面是题目要求,求指导,因为怕没有人回答.选为最佳答案后再给20分.1.1CarrierOpen Matlab.Set up a variable t,to represent time,with a range from 0 to 7.9
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一段关于matlab的英文求操作帮助要做matlab的实验,明天写.下面是题目要求,求指导,因为怕没有人回答.选为最佳答案后再给20分.1.1CarrierOpen Matlab.Set up a variable t,to represent time,with a range from 0 to 7.9
一段关于matlab的英文求操作帮助
要做matlab的实验,明天写.下面是题目要求,求指导,
因为怕没有人回答.选为最佳答案后再给20分.
1.1Carrier
Open Matlab.Set up a variable t,to represent time,with a range from 0 to 7.99 in steps of 0.01.These values are intended to represent time normalised to one bit duration.The time range thus represents a total of 8 bits.(Hint.Use t=0:0.01:7.99)
Now create a carrier signal,by making setting up a function called carrier(t),equal to the sine of 10π times t.Create a simple graph to check that this gives you a sinusoidal waveform with 5 cycles to every bit duration.(i.e.between time 0 and time 1,there should be 5 periods of the waveform).[Hint:Use plot options in matlab to drive a graph at your convenience).Now create your digital data waveform function,data(t),to represent the bit sequence 10110100 using unipolar line coding.You can do this by first setting up a column vector,D,with 8 rows,containing the data bits,and then replicating the components of D in order to obtain a vector D’ of same length as t; hint:since there is 5 cycles per bit duration,so each component of D will be replicated 5 times).
1.2 ASK Modulated wave
Create an ASK modulated waveform function ASK(t),by multiplying together data(t) and carrier(t).[Use matlab array point multiplication “.*”]
Plot graphs showing the digital data waveform and the ASK modulated waveform.
1.3 Square law demodulation
Demodulation of ASK can be carried out using a square law detector.[Hint:Use the formula given in the additional file at webCT.Look at “sum” function in matlab to implement the formula]
Produce a graph showing the square law output.Note that the output has a net positive average value during a ‘1’ bit period,and zero during a ‘0’ output.However,it also contains a high frequency component,because we have not filtered out the carrier harmonic.
In a real system,this would be done using a digital or analogue filter.In this simulation,you can do a crude approximation of this filtering process by taking a moving average over the last n samples,where n is a number you need to choose.Set up a suitable function to generate this average.Try to work out how to do this for yourself,but if you need a hint,look at the hint file on Web CT.If you get an error message saying "index out of bounds" when you do the averaging,redefine the lower limit of t locally so that you avoid negative arguments in the ASK (t) function within the summation.Work out,or do experiments to find,the best value for n.
Create a chart showing your filtered output,and compare this with the original data.
How would you use this filtered output to recreate the original transmitted data?
Filtering in this way is a crude example of digital signal processing,which you will study in greater detail in communications modules later in the course.
一段关于matlab的英文求操作帮助要做matlab的实验,明天写.下面是题目要求,求指导,因为怕没有人回答.选为最佳答案后再给20分.1.1CarrierOpen Matlab.Set up a variable t,to represent time,with a range from 0 to 7.9
1.1Carrier
打开MATLAB.设置的变量t表示时间,步长为0.01的范围内从0到7.99.这些值用来表示归一化到一个比特周期的时间.因此,该时间范围内的8位表示总.(Hint.使用T = 0:0.01:7.99)
现在,创建一个载波信号,通过建立一个功能叫做载体(T),等于10π时间t的正弦.创建一个简单的图形来检查,这给你一个正弦波形的5个周期的每一个位时间.(即在时间0和时间1之间,应该是5个周期的波形).[提示:在MATLAB中使用绘图选项,在您方便的图形驱动).现在创建的数字数据波形功能,数据(T),代表该位序列10110100单极线路编码.您可以做到这一点,首先设立一个列向量,D,与8行,包含的数据位,然后复制的组件的D,以便以获得矢量D'的相同的长度为t的;提示:由于有5每比特持续时间的周期,使各成分的D将复制的5倍).
1.2 ASK调制波
创建一个ASK调制的波形函数ASK(t)的数据相乘(t)和载波(吨).[使用MATLAB指向乘法“*”]
剧情示出的数字数据的波形和ASK调制波形.
1.3方法解调
可以进行使用平方律检波器的ASK解调.[提示:在WebCT的附加文件中给出的公式.在MATLAB中的“求和”功能来实现的公式]
生成的曲线图输出的方法.请注意,输出'0'输出期间,有一个净正平均值一个'1'位周期期间,和零.然而,它也包含了高频分量,因为我们没有过滤掉的载体谐波.
在一个实际系统中,这将是使用一个数字或模拟滤波器来完成.在这个模拟中,这个过滤过程中,你可以做一个粗略的近似,在过去的n个样本,其中n是一个数字,你需要选择移动平均线.设置一个合适的函数来生成这个平均.试图找出如何做到这一点的自己,但如果你需要一个提示,看看在Web CT提示文件.如果你得到一个错误信息,说:“索引超出范围”当你做平均,重新定义本地的下限吨,使您避免负面的论点在ASK(t)函数内的总和.工作,或做实验发现,最好的n值.
创建一个图表,示出过滤输出,并比较这与原始数据.
你将如何使用这个过滤输出重新创建原始发送的数据?
在这样的过滤是一个粗略的数字信号处理,更详细的通讯模块后面的课程中,你将学习的例子.