Frequency synthesizer for time base generator of level measuring device, has fractional frequency divider operated with periodical divider factor sequences whose periodical length is shorter in specified range

摘要

The synthesizer has a phase locked loop including a phase frequency discriminator, a rule oscillator, a fractional frequency divider and a loop filter. The fractional frequency divider is provided between a reference oscillator i.e. quartz oscillator, and the phase locked loop. The fractional frequency divider is operated with periodical divider factor sequences, and periodical length (T) of the divider factor sequences is shorter in range of 10 bit or less than 10bit, such that failure based on the divider factor sequences is restrained by the loop filter.