SPREAD SPECTRUM SIGNAL DEMODULATOR

摘要

PURPOSE: To apply inverse spread of a spread spectrum signal by generating a PN code accurately synchronously with a reception signal with a simple circuit configuration. CONSTITUTION: A PLL takes synchronization with a received spectrum and a PN code generator 18 generates a PN code and provides an output based on a clock signal obtained by frequency-dividing a carrier signal outputted from the PLL. A multiplier 30 multiplies an inverse spread signal obtained by multiplying the received signal with the generated PN code at a multiplier 10 with the carrier signal from a VCO 16. The signal obtained by multiplication is fed to a PN code synchronization detector 26 via a low pass filter 22, and the PN code synchronization detector 26 detects an asynchronizing state between the received PN code and the generated PN code. When the asynchronizing state is detected, a phase of a clock signal outputted from a 1/N frequency divider 20 is shifted based on the detection to adjust an output timing of a self-running PN code.