| 摘要 |
<p>1. A quickly variable frequency generator of the fractional division type, comprising a phase comparator (1), a first input (E1) of which is coupled to the comparison signal (Fr) input (E) of the generator, and having a second input (E2), a variable oscillator (5) having a control input which is coupled to the comparator, and an output which constitutes the generator output, and comprising a variable-module divider (7-8-9) which is inserted between the oscillator and the second input (E2) of the phase comparator (1), characterized in that the frequency generator comprises in series between the comparator (1) and the control input of the oscillator (5) a window circuit (2) which truncates the duration of each output signal of the comparator (1) by a given value T which depends on the maximum duration (d phi) of the phase shift due to the fractional division in the operational frequency bandwidth of the generator, in such a way that the phase jitter due to the fractional division does not impair the spectrum of the generator output signal.</p> |
