pll frequency synthesizer for frequency hopping systems, especially with direct modulation frequency

摘要

frequency synthesizer with ring phase lock (pll) able to carry out quickly the change of frequency and to modulate directly the frequency generated.includes a filter ring (lb) with a cutoff frequency high for the rapid transition during the transitional stage of transition from one frequency to another.circuit and a filter ring (bs) with frequency of cut low to the operating system.in the filter narrowband (bs) is provided for the presence of a circuit for sampling and preservation (sh) formed by a buffer (a) whose gate is tied to a capacitor (c) via a breakuttore (s2) which remains closed during the transient of transition from one frequency to another, and a separator (a1) to take as a reference of the narrow band filter, the voltage sampled.(figure 3).