| 摘要 |
PURPOSE:To obtain a mobile radio equipment making a transmission reception frequency highly stable by forming a PLL controlling a 1st reference oscillation frequency so as to control an intermediate frequency deviation to be equal to the frequency deviation of a 2nd reference oscillator. CONSTITUTION:A received radio wave FR of an antenna 1 is mixed with an output FLO+ or - FLO by a frequency mixer 12 via an antenna multicoupler 2 and an RFAMP 11 to obtain an intermediate frequency signal FIF =¦FR-FLO+ or - FLO¦. The signal FIF is amplified by an IFAMP13, the phase of its output is compared with the frequency FLO+ or - FLO fed from a reference oscillator 14, its error voltage output is fed back to a reference oscillator 6 in a frequency synthesizer B via an LPF 16 and the oscillated frequency of the VCO 7 is controlled so that the oscillated frequency of the oscillator 14 is FIF+ FIF=¦FR-FLO+ or - FLO¦ by using a PLL comprising the VCO7, a frequency divider 8, a phase comparator 9 and an LPF 10. In this case, since the relation of FIF=FR-FLO exists, the frequency division is expressed as FIF = FLO and the transmission reception frequency is made highly stable. |
