PLL frequency synthesizer, in particular for frequency hopping systems with direct frequency modulation.

摘要

PLL frequency synthesizer suitable to carry out fast frequency hopping and to modulate directly the generated frequency. It includes broadband filtering means (LB) for the quick transition during the hop from one frequency to another, and narrow band filtering means (BS) for the operation conditions. The narrowband filtering means (BS) include: <UL ST="-"> a sample and hold circuit (SH); a narrow band filter (RS); a buffer connected between said sample and hold circuit (SH) and said narrow band filter (RS). </UL> <IMAGE>