Single loop frequency synthesizer with direct digital synthesis
AssigneeThomson-CSF
InventorsElie Brunet, Jean-Noel Brasselet, Eric Souchard
Life of this patent
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Abstract
A frequency synthesizer with very short acquisition times. With a single loop there is associated a direct digital synthesizer whose signal is injected into the loop by means of a mixer. The adjustment of the loop is done on Np.Fr and the adjustment of the digital synthesis is done on (Ns+)Fr with Np, Ns, K and M as integers, Np being greater than Ns, 0.ltoreq.K<M, M as a fixed value and where Fr is a reference frequency. The mixture makes it possible to obtain, as a synthesis frequency, (Ns+Np+)Fr. The acquisition time of the digital synthesis is negligible and that of the loop is greatly reduced since it synthesizes steps that are multiples of Fr and not of as with a standard single loop.
Claims5
A single-loop frequency synthesizer to give a synthesized frequency that can be written as (N+)Fr where Fr is a frequency, N, K and M are integers with N and M being positive numbers and K being smaller than M in absolute value, this synthesizer comprising a single loop, a reference oscillator to give a signal at the frequency Fr, a mixer having a first input and a second input and an output, the mixer having its first input and its output arranged serially in the loop, and a direct digital synthesizer device having an output connected to the second input of the mixer, the direct digital synthesizer device producing, from the signal at the frequency Fr, a signal at the frequency (Ns+)Fr where Ns is a positive integer smaller than N.
Dependencies are inferred from the claim text.