RECEIVER FOR CDMA SYSTEM RADIO DATA

摘要

PROBLEM TO BE SOLVED: To conduct automatic gain control so as to minimize an error rate of reception data even when interference from other channel subject to code division multiplex is high in the direct spread spectrum (CDMA) system as a transmission system of a digital signal. SOLUTION: A transmitter side inserts a known bit to transmission information and sends the result, a receiver side uses the known bit, a known bit collation circuit 19 measures an error rate of a reception signal, and a control circuit 20 controls setting of a level of automatic gain control so as to minimize the error rate. Thus, a required bit number of an A/D converter 15 is reduced and limited A/D conversion accuracy is effectively utilized. The measurement of the error rate may be attained by using error rate information from a Viterbi decoder decoding an error correction convolution code sent from the transmitter side.