A transmission data D is subjected to buffering by a buffer circuit 13 and fed to an encoder 12. The PN code string PN00 outputted from the PN code string generating circuit 11 or the PN code string subjected to a delay of 2T each in a delay circuit 14 is fed to an input terminal...
the transmission side is a desired signal by multiplying a reception spread spectrum signal and a signal retarding the said reception spread spectrum signal at the reception side and extracting a low frequency component of the multiplied signal so as to obtain a demodulation signal and outputting it...
Transmitter Using spread spectrum communication system, a receiver, a communication system and communication method PROBLEM TO BE SOLVED: To provide a multi-carrier/spread spectrum transmitter, its receiver, a system and method for communications using these which show e... 加藤 英樹,山崎 慎一,関 ...
Operation of direct sequence spread spectrum coding and decoding. In this case, it can be seen that chip stream (a) is repeated in waveform (h). This is multiplied by (g) to give the waveform (i). Each group of four bits (as there are four bits in the chip code used in the ...
It shares key techniques such as Frequency Hopping (FH) and Direct Sequence Spread Spectrum (DSSS), with a focus on DSSS due to its widespread industry use. It explains the process of spreading and despreading signals, the role of m-sequences in generating pseudonoise sequ...
The despreading process in the receiver will spread the spectra of unwanted narrowband signals, thus improving interference rejection. The chapter concludes with the explanation of different types of the spread-spectrum techniques including time hopping, direct sequence, and frequency hopping....
Communication device of the spread spectrum system, and its high-speed synchronous established method A device for spread spectrum communication is provided which enables synchronization at a high-speed even if the carrier frequency and the phase are not known precisely on the receiving end. The ...
In this chapter we of course do not intend to cover the topic of spread spectrum comprehensively. We just want to lay the theoretical background of spread spectrum for a sufficient understanding of the CDMA technology and its application within UMTS. As in the foregoing chapters we have ...
Spreadspectrumtechniquesspreadinformationoveravery largebandwidth–specifically,aband-widththatismuchlarger thantheinverseofthedatarate. 3 Origins “spreadspectrum”comesfromthemilitaryarea,wherethemain interestliesinkeepingcommunicationsstealthy,safefromintercept, ...
As in many other modulation systems, the modulated baseband signal x(t) has a much higher rate than the message, and as such its spectrum is much wider than that of the message that is already wide given that it is a sequence of pulses. This can also be seen by considering that x(t...