FREQUENCY SOURCE WITH IMPROVED PHASE NOISE

摘要

A frequency source with improved phase noise. In one embodiment a phase-locked loop is used as a component of a frequency source and a signal to noise enhancer (SNE) is used to suppress phase noise produced by the phase-locked loop. The signal to noise enhancer is a nonlinear passive device that attenuates low-power signals while transmitting high power signals with little loss. The signal to noise enhancer may be fabricated as a thin film of yttrium iron garnet (YIG) epitaxially grown on a gadolinium gallium garnet (GGG) substrate, the GGG substrate being secured to a microwave transmission line from the input to the output of the signal to noise enhancer, such that the thin film of yttrium iron garnet is close to the transmission line.

主权项

1. A frequency source, comprising:
a phase-locked loop, having an input and an output; and a first signal-to-noise enhancer (SNE) having an input and an output, the input of the SNE being connected to the output of the phase-locked loop, the first SNE comprising:
a microwave transmission line connected between the input and the output of the first SNE;a magnetic component capable of supporting magneto static waves, the magnetic component secured in proximity to the microwave transmission line;one or more magnets secured in proximity to the magnetic component; the first SNE having the characteristic of allowing a signal to propagate from the input of the first SNE to the output of the first SNE:
with a first attenuation when the power of the signal at the input of the SNE is less than a first threshold, andwith a second attenuation when the power of the signal at the input of the SNE is greater than a second threshold, the first attenuation exceeding the second attenuation by at least 5 decibels (dB).