| 摘要 |
PROBLEM TO BE SOLVED: To surely make a lock frequency and the frequency of local oscillation frequency signals be different by locking a frequency synthesizer only by the frequency which is the multiple of the local oscillation frequency signals by a band-pass filter. SOLUTION: This frequency synthesizer is provided with a first oscillator 8 for outputting the local oscillation frequency signals based on control signals, the band-pass filter 9 for passing through predetermined multiplication waves among the frequency of the local oscillation frequency signals, a second oscillator 4 for outputting reference frequency signals and a control circuit for detecting the phase difference of the output signals of the band-pass filter 9 and the reference frequency signals and outputting the control signals, etc. Then, since the frequency synthesizer is locked by the frequency of the signals passed through the band-pass filter 9, the frequency synthesizer is locked only by the multiplication waves of the frequency of the local oscillation frequency signals at all times. |
