| 摘要 |
PURPOSE:To realize brief and stable synchronization by performing diffusion modulation with wide-band diffusion codes and by separating respective circuits while sharing the same frequency band. CONSTITUTION:A received signal (Rx Signal) is passed through an antenna and high-frequency amplifier and then converted by mixer 21 into an intermediate- frequency signal. A synchronizing signal, included in the received signal, is separated from a diffusion information signal by narrow-band filter 22, amplified by amplifier 23 and phase-synchronously detected by synchronous detector 25 to be extracted as the synchronizing signal. The output of this detector 25 is applied to multiplier 26 to generate the bit-synchronizing clock of diffused codes and while the clock tracking loop consisting of position detector 27 and VCO28 is controlled, controller 30 which controls the start of reverse diffusing code generator 29 is controlled. Consequently, the synchronized signal is correlatively detected by the correlator composed of multiplier 31, etc., and demodulated by demodulator 34 to a high-pitched tone. |
