| 摘要 |
PURPOSE:To a frequency synthesizer which can be switched to a desired frequency at a high speed. CONSTITUTION:A phase comparison means 3 of the frequency synthesizer compares a phase of a variable frequency divider output signal fv with a reference frequency signal fr and counts a pulse width in response to a phase lead or lag and applies D/A-conversion convert the county value directly into a DC control voltage of a voltage controlled oscillator(VCO) 5 and is featured to preset the frequency data to initialize the DC control voltage of the VCO 5 oscillating an object frequency at the frequency changeover. |
