FREQUENCY SYNTHESIZER WITH FAST TUNING

摘要

A frequency synthesizer of a type having a variable frequency divider includes a loop for locking the phase of a voltage-controlled oscillator (1), a search tuning loop in which, after a change in the displayed frequency, a digital search tuning data is formed which is converted into the control voltage for the oscillator. This synthesizer also includes translating means (9b) for translating the displayed frequency data into a digital presetting data whose values characterize sub-ranges to which the displayed frequency may belong, and means (14) for converting the said digital presetting data into a presetting voltage which is used to control the frequency of the oscillator, the values of the presetting voltage being determined to produce substantially the starting frequencies of the sub-ranges while the variation of the search tuning voltage is determined for producing a frequency variation which is substantially equal to the width of a sub-range.