MULTIPLEX RADIO TRANSMITTING DEVICE AND METHOD THEREFOR, MULTIPLEX RADIO RECEIVING DEVICE AND METHOD THEREFOR, AND MULTIPLEX RADIO TRANSMITTING AND RECEIVING DEVICE AND SYSTEM MULTIPLEX RADIO TRANSMITTING AND RECEIVING

摘要

PROBLEM TO BE SOLVED: To attain flexibility of members to be used and to improve the cost performance radio by converting the frequencies of 1st and 2nd intermediate frequency signals by means of the 1st and 2nd local signals respectively. SOLUTION: A 1st frequency converter 3a up-converts a 1st IF signal, which is outputted from a digital modulation part 2a into a 2nd IF signal which has frequency higher than that of the 1st IF signal by the frequency of a 1st local signal. A 1st band filter 54a eliminates the frequency component of the 1st local signal out of those signals, which are outputted from the converter 3a and passages only the 2nd IF signal. A 2nd frequency converter 5a up-converts the output from the filter 4a by means of a 2nd local signal to output a radio frequency signal. A 2nd band filter 6a filters the radio frequency component outputted from the converter 5a and removes the frequency component of the 2nd local signal.