Frequency conversion system with improved spurious response and frequency agility

摘要

A frequency conversion system with improved performance. In one embodiment an image reject mixer is used to perform frequency conversion providing an initial degree of suppression of the image and local oscillator leakage signals, and a signal to noise enhancer (SNE) is used to further suppress the image and local oscillator signals, the signal to noise enhancer being 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 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 system for frequency conversion, the system comprising:
an image reject mixer, configured:
to receive a local oscillator input signal and a modulation signal, andto produce a modulated output signal, comprising:
a first modulation sideband signal,a local oscillator output signal, anda second modulation sideband signal,the power in the local oscillator output signal being at least 5 decibels (dB) less than the power in the first modulation sideband signal, andthe power in the second modulation sideband signal being at least 5 dB less than the power in the first modulation sideband signal; and a signal-to-noise enhancer (SNE) having:
an input connected to receive the modulated output signal from the image reject mixer; andan output,the SNE comprising:
a microwave transmission line connected between the input and the output of the SNE;a magnetic component capable of supporting magnetostatic waves, the magnetic component secured in proximity to the microwave transmission line;one or more magnets secured in proximity to the magnetic component;the SNE having the characteristic of allowing a signal to propagate from the input of the SNE to the output of the 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 dB.