基带信号的码型（The code type of baseband signal）.doc

基带信号的码型（The code type of baseband signal） Baseband signal The receiving signal is the receiving signal after the decoding of the rf signal. In the launch, it is the pre-modulated transmission signal, that is, encoded but not modulated. Youre used to calling it I and Q. However, in fact, due to the development of chip technology, the baseband signals are transmitted in the form of data flow in the plane, such as V70. ... You are not measuring the baseband signal, the jump - variable dc level, the base band signal is 67KHz, the most obvious in the samsung 600 cell phone. No more: digital oscilloscopes have no analogue in mobile phones, especially in the case of mutant signals. 4.1 code type of digital baseband signal 4.1 code type of digital baseband signal Here is the gist of the book: The code design principle of digital baseband signal is commonly used in the code type digital baseband signal power spectrum 4.1.1 code design principles of digital baseband signals The so-called digital baseband signal is the electrical pulse of the message code. In actual baseband transmission system, not all of the original digital baseband signal can transfer in the channel, for example, contains rich dc and low-frequency components of baseband signal is not suitable for transmission in the channel, signal because it has the potential to cause serious distortion; For example, a normal baseband transmission system can extract the bit sync signal from the received baseband signal, while the bit synchronization signal depends on the code type of the code, if the code appears for a long time The 0 symbol, then the baseband signal can appear at 0 It is difficult to ensure the accuracy of the bit synchronization signal. The actual baseband transmission system may also present other requirements, which can lead to various possible requirements for baseband signals. In conclusion, there are two main requirements for the baseband signal of transmission. (1) the original information symbol