| 摘要 |
PURPOSE:To obtain an effective phase noise characteristic over a wide range by outputting a signal obtained by mixing the output signals of the 1st and 2nd VCOs by a mixer from frequency synthesizer. CONSTITUTION:The 1st PLL is constituted of the 1st variable frequency divider 4, the 1st phase comparator 5, the 1st low pass filter(LPF) 6, the 1st voltage- controlled oscillator(VCO) 1 for controlling the outputted oscillation frequency in accordance with the output voltage of the LPF 6, and the mixer 3 for mixing the output signals of the 1st and 2nd VCOs 1, 2 and supplying the mixed signal to the frequency divider 4. On the other hand, the 2nd PLL is constituted of the 2nd variable frequency divider 7, the 2nd phase comparator 8, the 2nd LPF 9, and the 2nd VCO 2 for controlling output oscillation frequency in accordance with the output voltage of the LPF 9 and supplying the controlled signal to the frequency divider 7. The absolute value of a difference between the frequency dividing ratios N, M of the 1st and 2nd variable frequency dividers 4, 7 is held at a fixed value and an output signal from the mixer 3 is extracted as an output signal from the frequency synthesizer. |
