| 摘要 |
PROBLEM TO BE SOLVED: To provide a digital synchronization follow-up circuit using a loop filter of a simple constitution without using a voltage controlled oscillator(VCO). SOLUTION: Received base band signals are inverse-spread in an early correlation device 1 and a late correlation device 2 respectively to which spreading codes with a phase shift of ±Δ to a reference position are set and integrated during a symbol length for each chip CLK, and binary up/down signals are generated by obtaining a difference in the integrated values in a comparator 3. In a loop filter 4, the binary signals are counted, and when it reaches respective values set for the phase control of the early side and the late side, a chip CLK phase adjustment device 6 is instructed so as to advance and delay a phase set beforehand, the phase is adjusted in respective correlation devices through a spread code generator 7 and synchronization is followed up. |
