| 摘要 |
PURPOSE:To reduce power consumption by using only one mixer operated at a high frequency band having been required for two mixers with respect to the direct conversion receiver for an FSK signal for radio communication. CONSTITUTION:The output of a local oscillator 103 is distributed into an in- phase signal and an orthogonal signal whose phase differs by 90 deg. at a 90 deg. phase shift distributer 104, direct spread means 107,108 apply direct spread processing by using the output of the spread code generating means 105, 106 respectively and a synthesis means 109 synthesizes them to conduct code division multiplex. A mixer 102 mixes it with an FSK signal by using the multiplex signal and spread codes 116, 117 used for code division multiplex are used at a base band and inverse spread means 110,111 apply inverse spread to separate the in-phase component and the orthogonal component and low pass filters 112, 113 apply band limit respectively to obtain I,Q signals and an orthogonal demodulation means 114 conducts orthogonal demodulation. |
