Receiver for spread spectrum communication system capable of shortening acquisition time

Abstract

A receiver is provided for use in a spread spectrum communication system for receiving a spread spectrum signal having a modulated PN code, the receiver including: an analog-to-digital converter for sampling an input signal in synchronization with a first clock signal, and generating a sampled signal. The first clock signal having n times a frequency of a chip clock signal. Also included is a counter for a counting a number of clocks of the first clock signal to generate a selection signal; a pseudonoise code generator for generating a substantially replica pseudonoise code signal in synchronization with a second clock signal having the frequency of the chip clock signal; a memory for storing the sampled signal in synchronization with the second clock signal; a selector for selecting one of the sampled signals stored in the memory in response to the selection signal; a demodulator for demodulating the pseudonoise code signal from the sampled signal; an accumulator for accumulating outputs of the demodulator during a cycle of the second clock signal to generate an accumulated acquisition value; and a comparator for comparing the accumulated acquisition value with a threshold value, generating an acquisition success signal if the accumulated acquisition value is greater than the threshold, and generating a hold signal if the accumulated acquisition value is less than the threshold,