Reception apparatus for A/D conversion of a received signal

摘要

A reception apparatus whose A/D converted digital signal does not contain a DC signal component. I and Q signals obtained by orthogonally demodulating a received signal are supplied via coupling capacitors 1 and 11 to A/D converters 2 and 12 to A/D convert the I and Q signals into digital signals which are supplied to a demodulator 31 to demodulate them. The output of the demodulator 31 is supplied to a DC component level detector 41 to detect DC component levels of the demodulated digital signals. The detected DC component levels are supplied to D/A converters 51 and 52 to convert them into analog signals. The DC bias values of the A/D converters 2 and 12 are controlled by the converted analog signal levels to eliminate the DC component from the digital signals converted by the A/D converters 2 and 12.