Single-loop frequency synthesizer and electronic assembly comprising such a synthesizer

摘要

The invention relates to frequency synthesizers with very short acquisition time. A single loop (1, 4, 6, 7, 8, 9) is combined with a digital direct synthesis device (21, 22, 23) the signal of which is injected into the loop by virtue of a mixer (7). Setting-up of the loop is done on Np.Fr and that of the digital synthesis on IMAGE with Np, Ns, K and M integers, Np large compared with Ns, 0 /= K M, M fixed, and in which Fr is a reference frequency; mixing makes it possible to obtain, as synthesis frequency, IMAGE The time to acquire the digital synthesis is negligible, and that of the loop very much reduced due to the fact that it synthesizes multiple steps of Fr and not of Fr DIVIDED M as with a conventional single loop. Application to all electronic assemblies requiring fast synthesizers.