| 摘要 |
PURPOSE:To obtain a PLL circuit whose frequency switching circuit is very high and the transmission frequency stability is high without incurring the increase in circuit components such as a multiplier or a mixer by using in common a transmission local signal and a phase comparison frequency signal of the PLL. CONSTITUTION:The PLL circuit C is used for the transmission circuit system A and a reception circuit system B to apply a local oscillation signal in a radio communication equipment, an output of a reference signal generator 7 is subject to P multiplication at a P multiplier 23, then mixed with an output of a VCO13 by a mixer 22 to shift the frequency. The signal subject to frequency shift is fed, on one hand, to a prescaler 11 via a BPF21 and fed, on the other hand, to the transmission circuit A. Thus, a PLL synthesizer circuit with simple circuit constitution and high transmission frequency stability is obtained. Since the input frequency of the prescaler is shifted to a low frequency, the power consumption of the prescaler is reduced. |
