Automatic calibration device for direct spectrum spread receiver

摘要

A simulated reception signal is produced by modulating an AC signal having the same frequency as the reception frequency with a modulating signal produced using two pseudo noise codes delayed by 1/2 or 3 chips. In a calibrating mode, in which the simulated reception signal is chosen, a reference voltage to a comparator for synchronization detection and an output voltage of a differential amplifier for synchronization holding are stored in a CPU. In a receiving mode, in which an actual reception signal is chosen, the CPU controls the comparator and a pseudo noise generator which is included in a delay lock loop on the basis of the stored data.