Direct Sequence Spread Spectrum (DSSS) Communication – Communication Principle

Principle: The principle of the Direct Sequence Spread Spectrum system is very simple. For example, a string of information to be sent is expanded to a very wide frequency band through PN code. At the receiving end, the information sent is retrieved by correlating the spread spectrum signal with the same PN code used for expansion at the sending end.

Depth principle: First, it directly uses the spread spectrum code series with a high code rate to spread the spectrum of the signal at the transmitter by using various modulation methods, and then it uses the same spread spectrum code sequence to decode at the receiver to restore the spread spectrum signal to the original information. How to spread the spectrum specifically: In fact, a digital modulation method is used. Specifically, a certain PN code (pseudo-noise code) is used to add the signal source. For example, when the transmitter needs to transmit signals, replace “1″ with 110001000110 and “0″ with 00110010110. This process realizes a wide spectrum. At the receiver, if the received sequence is 110001001110, it will be restored to “1″ and if it is “00110010110,” it will be restored to “0″. This is called “breading. In this way, the signal source rate is increased by 11 times, and the processing gain is more than 10dB, which effectively improves the multiple noise ratio of the whole machine. 
The RF bandwidth of the DSSS system is very wide. Therefore, a small part of the spectrum will not cause serious fading of the signal spectrum, which is one of its advantages. DSSS is excellent in its security, which is why the US military mainly used it for wireless transmission during World War II.

The above is the knowledge explanation of the Direct Sequence Spread Spectrum (DSSS) Communication - Communication Principle brought to you by Shenzhen HDV Optoelectronic Technology Co., Ltd., a manufacturer of optical communication equipments. hope this article can help you to increase your knowledge. Thanks for reading this article.