Question

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，具体怎么做，谢谢。
先给10分，因为怕没有人回答。选为最佳答案后再给20分。谢谢
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.
谢谢帮助！

Answer 1

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。

追问

你这是直接google翻译的吧= =

追答

是的，有工具为什么不用呢！

追问

Can you explain it to me= =

Answer 2

one bit duration这里就没理解上去，惭愧啊