The second step: systematically review the basic theory and master the ins and outs of each formula. To the point where you can infer subtly.
The focus of this step is still the second and third chapters, especially the second chapter. First read the book in combination with the undergraduate handout, then think about the process and deduce it yourself. 1, to be able to deduce how the Fourier series came about, this can be found in the chapter on advanced mathematical series. 2. Deduce how to get Fourier transform from Fourier series and why there is an additional 2π in denominator, which can be found in Chapter 3 of Signals and Systems. 3, to personally derive the Fourier transform of various functions, do not be afraid of trouble, so as to learn well. 4. Derive the properties of Fourier transform, including symmetry, time shift and frequency shift. Deduction is good for memory. 5. Derive the related contents of Hilbert transform. 6. Chapter II Other knowledge, don't learn by rote, pay attention to understanding more.
The third chapter may be difficult for students who have never studied stochastic process, but they should keep learning. Go through it first, see what you can understand, and then do it again. When you encounter difficulties, jump over first and try to understand as much as possible every time. Don't deduce some unnecessary and troublesome knowledge, such as Rayleigh distribution. Look at it several times until there are a few points to skip. If you really don't understand, put it down first and review it later.
Step 3: Learn the knowledge of communication principles in depth, and be aware of it. After reviewing the basic principles, you should study others deeply. The goal of this step is to target the fourth, fifth and sixth chapters.
These three chapters are very rich, so be careful not to read them all in a few days, because the effect will not be very good. Review is still to read the book once or twice, then sum up the knowledge, and then deduce it yourself. There are many things to be deduced in these chapters, so don't try to remember the conclusions. If you don't understand, you won't remember it. Now the postgraduate entrance examination (forum) topic is very lively, and the test is a deep understanding of the basic principles.
The fourth chapter is all kinds of modulation methods and their anti-noise performance. They are easy to understand, have a lot of knowledge and are easy to mix, so we should always consolidate our practice. The content of this chapter is well summarized in the book "Communication Principle Learning and Postgraduate Entrance Examination Guidance". As for other biased knowledge points, you can look at them in the future.
Step 4: Do exercises and read tutorials and handouts. Achieve the actual improvement of examination ability.
Of course, this step is best followed by the third step, and the effect will be better. The problem is mainly from the problem set to the sixth chapter. The topics in the problem set are mainly the after-school exercises in the textbook, and some of them are supplementary. Anyway, these questions are very good, typical and have good answers (of course, some questions have good answers, and you will find better and simpler methods if you understand them yourself).
It is not an exaggeration to do the problems in a centralized way once or three times. When doing these questions, it is best to combine them with textbooks. Doing the problem depends on the relevant content of the textbook and how to apply the deduction of the textbook to solve the problem. There are still some topics that you may not see at all when reading, or feel particularly complicated and skip. After combining the topics, you should try to understand all the knowledge of the whole book. Of course, some topics are very complicated. If you really don't understand them, just skip them and save them for later.
The fifth chapter is to understand various code types, including his graphics (whether to return to zero), spectrum and applications. These are easier to fill in the blanks. Then the most important bit error rate analysis. According to the order of teaching materials, the error analysis under signal condition is determined first, and then the error analysis under random signal condition is determined. If you find it too difficult at first, you can just remember some conclusions and understand them later. I didn't pass the eye chart, just look around, the channel is generally balanced, and I have a little understanding, so I'll talk about it when I do the problem.
The sixth chapter is rich in content and can be studied in parts. First of all, look at the parts of ook, 2FSK, 2PSK and DPSK, because they are all binary and elementary knowledge, which is relatively easy and needs to be understood emphatically. Then we should learn quaternary QPSK and DQPSK, and learn how to change from one branch to two branches, which is very helpful for understanding M-ary modulation. Finally, M element, with emphasis on signal space and constellation diagram. It is also important to deduce the error rate of M-ary, which is derived on the basis of binary. Please note that there are many cases of error code derivation in this chapter. Just master the best reception (matching reception) under Gaussian white noise interference, and leave the rest alone. It's not too late to see it later.
Step 5: Learn the contents after Chapter 7 and complete the preliminary review of the whole book.
The content after the seventh chapter is relatively easy, without too many complicated principles, and it is similar to the content of the computer, but it is still often taken in the exam, and the score ratio is still relatively large. I think this part of the score should be firmly grasped.
In the review process, read the textbook first, and then do the problem set. The whole chapters 7, 8, 9 and 10 still have a large amount of calculation, such as entropy calculation, channel capacity calculation and various codes calculation. We must do more work to achieve accuracy, and we can't just be roughly correct. We must never be conceited. There are few steps in this kind of question in the exam, and a small mistake will lead to many points. Be careful.
Also, when learning various codes (linear block codes, cyclic codes, convolutional codes, M-sequence), you can compare them yourself and sort out their relationships, especially the coding circuits, so as to avoid confusion. The biggest feeling of learning this part is to write more, sort out your own understanding and summarize more. Don't just read and do nothing. Although these chapters are not difficult, don't be too careless.
Step 6: Consolidate the whole book knowledge and form the structural system of the whole communication principle course.
This time it is mainly based on textbooks and problem sets. Considering that the previous review is to review each chapter separately, you may feel very confused, so you should clear your mind and build a curriculum system. The main thing is to do all the questions in the problem set and try to deduce them yourself. Of course, it is still difficult to do so, but try your best to do it. There are still some parts that I didn't understand before, so I just skipped them. This time, we should start trying to learn more. Every time I read the book, I will feel that I have some deeper understanding, which will not be a simple repetition.