SPREAD SPECTRUM RADIO TRANSMISSION DIGITAL MOBILE COMMUNICATION DEVICE

摘要

A spread spectrum radio transmission digital mobile communication device having a RAKE receiving function which is hardly influenced by delayed waves having delay time shorter than the chip time width of spread-spectrum signals or same-channel interference waves. It is provided with an inverse spreading means (111) which correlates received signals with spread-spectrum signals so as to perform inverse spreading and a synthesizing means (113 and 115) which delays inversely spread signals according to the path and performs path synthesization. A plurality of receiving branches (101-i), variable gain amplifying means (102-i) which respectively adjust the amplification factors of the signals received by the branches (101-i), adding means (103) which adds the signals outputted from the amplifying means (102-i) and inputs the sum to the inverse spreading means (111), and gain control means (104) which controls the amplification factors of the amplifying means (102-i) so as to reduce the influence of delayed waves having delay times shorter than the chip time width of spread-spectrum signals of the signals inputted to the inverse spreading means (111). Thus, by adding constitution of an adaptive antenna which controls the directivity of a reception antenna to a spread-spectrum radio digital mobile communication device having a RAKE function, the influence of same-channel interference waves or delayed waves having delay times shorter than the chip time width of spread-spectrum signals which are not coped with by the RAKE receiving function is reduced.