| 摘要 |
PURPOSE:To prevent the deterioration is S/N of an output signal without changing the output phase at fluctuation of an input frequency by extracting a required band from an input signal, frequency-dividing it, phase-shifting one of its outputs on one hand, multiplying the other on the other hand and mixing both the outputs. CONSTITUTION:The required band is extracted from the input signal through a BPF12 and is frequency-divided by a frequency-divider 13. An output of the frequency-divider 13 is shifted in terms of phase by a phase frequency characteristic circuit 14, and on the other hand a frequency component multiplying an output frequency of the frequency divider 13 is generated by a multiplication means 15. Further, a mixer 16 mixes the output of the circuit 14 and the means 15 and outputs a difference frequency component. As a result, the output phase is made unchanged even if the input frequency is fluctuated and the deterioration in the S/N of an output signal is prevented. |
