| 摘要 |
PURPOSE:To obtain a stable synchronization decision signal by providing a window comparator connecting between a receiver output and a synchronizing detector and supplying a signal only in excess of a setting level of the window comparator to a synchronizing detector. CONSTITUTION:An incoming spread spectrum signal is mixed with a pseudo noise signal generated by a PN code generator 2 at a mixer 1, and a signal representing the correlation of both the signals is demodulated by a data demodulator 3. A demodulated output in the asynchronous state is entirely noise and when the synchronization is taken, the demodulated output exists only at a positive or a negative level. A window comparator 9 detects only a signal at a level in excess of the setting range and its detection signal is integrated by an integration circuit 7. When a signal over the setting level in the signals is detected as a synchronizing signal by a synchronizing detection circuit 8, stable synchronization is detected even when a level of data is logical '0' or logical '1'. |
