SPREAD SPECTRUM COMMUNICATION SYSTEM

摘要

PURPOSE: To start synchronization locking from any initial phase difference by providing a synchronization spread code with a period being a specific multiple of that of a code generating timing signal and a local reference signal so as to eliminate the need for modulation of information of the local reference signal. CONSTITUTION: A code generator 8 generates an inverse spread code of a code series length L and a local reference signal PNO* of a code series length 2L based on a same clock signal. A signal PN0 is a synchronizing signal included in a reception signal S1 and the signal PNO* is a signal being inverse of the PN0 on time base. In this case, a correlation peak output S4 as shown in caption 215 is a signal led byΔ/2 from a code generating timing signal S6 shown in caption 216. Then synchronization locking and synchronization tracing are attained by giving the correlation peak output S5 and the code generating timing signal S6 to a PLL 7. Since it is not required to modulate the local reference signal different from a conventional system, the correlation peak signal at out of synchronism is not lost and the synchronization locking is attained from any initial phase difference.