| 摘要 |
PURPOSE:To contrive the stabilization of the frequency switching by applying setting change to a frequency division data in a frequency divider and to a preset voltage of a D/A converter synchronously based on a pulse timing of a reference signal. CONSTITUTION:A frequency divider 4 fetches a frequency setting data based on a pulse timing of a frequency division signal synchronized with the reference signal at the phase lock by a phase detector 1. Moreover, the frequency setting data to the D/A converter 6 is switched based on a control signal outputted from a control section 17 based on the reference signal. Thus, the frequency switching by the frequency divider 4 and the D/A converter 6 is applied synchronously. Thus, the initial phase error at changeover is minimized and made constant so as to attain stable frequency changeover. |
