Acousto-optic rf spectrum analysis method and apparatus

Claim 2

In a method for separating the different frequency components of a radio frequency signal, the steps of exciting an acoustic wave in an optically anisotropic medium at the frequency of the radio frequency signal to be frequency separated, collinearly diffracting a beam of light of selected bandwidth on the acoustic wave within the optically anisotropic medium to diffract light of a first polarization and of a frequency within said selected bandwidth related to the frequency of the acoustic wave into light of a second polarization, analyzing the diffracted output light beam to separate light of the second polarization from light of the first polarization, and spectrum analyzing the separated light within the selected bandwidth to provide spatial separation of the light to provide information concerning the different frequency components of the radio frequency signal, providing an output indication of the spectrum of the components of the radio frequency signal, and attenuating the intensity of the spatially separated light along a gradient aligned substantially normal to the spatial separation of spectral components to provide light-intensity indications at the spatial separations of the light that are representative of the amplitudes of the corresponding frequency components of the radio frequency signal.

Claim 3

The method of claim 1 wherein the step of spectrum analyzing the separated light comprises the step of spectrum analyzing the separated light of the second polarization.

Claim 4

The method of claim 1 wherein the step of spectrum analyzing the separated light comprises the step of spectrum analyzing the separated light of the first polarization.

Claim 5

The method of claim 1 wherein the beam of light is a beam of white light.

Claim 6

Acousto-optic apparatus comprising optically anisotropic medium means, means for exciting an acoustic wave in an optically anisotropic medium means at a frequency related to a radio frequency input signal, source means for introducing into said anisotropic medium means a beam of light having a selected bandwidth and having a first polarization to collinearly diffract on the acoustic wave within the optically anisotropic medium means the light of the first polarization and of a frequency related to the frequency of the acoustic wave into light of a second polarization, means for analyzing the diffracted output light beam to separate light of the second polarization from light of the first polarization, means for spectrum analyzing the separated light within said selected bandwidth to produce a spatial separation of the light according to frequency of the light to provide information concerning the different frequency components of the radio frequency input signal, displaying means for providing an indication of the spectrum of the radio frequency input signal, and light attenuating means disposed in the light path of the spatially separated light through which such light is projected toward said displaying means, said attenuating means having a gradient of attenuation oriented generally normal to the direction of spatial separation of the light beam to provide light-intensity indications at the spatial separations of the light that are representative of the amplitudes of the corresponding frequency components of the radio frequency input signal.

Claim 7

Acousto-optic apparatus comprising optically anisotropic medium means, means for exciting an acoustic wave in an optically anisotropic medium means at a frequency related to a radio frequency input signal, source means for introducing into said anisotropic medium means a beam of light having a selected bandwidth and having a first polarization to collinearly diffract on the acoustic wave within the optically anisotropic medium means the light of the first polarization and of a frequency related to the frequency of the acoustic wave into light of a second polarization, means for analyzing the diffracted output light beam to separate light of the second polarization from light of the first polarization, means for spectrum analyzing the separated light within said selected bandwidth to produce a spatial separation of the light according to frequency of the light to provide information concerning the different frequency components of the radio frequency input signal, displaying means for providing an indication of the spectrum of the radio frequency input signal, and light attenuating means disposed in the light path of the spatially separated light through which such light is projected toward said displaying means, said attenuating means having a gradient of attenuation oriented generally normal to the direction of spatial separation of the light beam to provide light-intensity indications at the spatial separations of the light that are representative of the amplitudes of the corresponding frequency components of the radio frequency input signal.

Claim 8

The apparatus of claim 5 wherein said means for spectrum analyzing the separated light comprises means for spectrum analyzing the separated light of the second polarization.

Claim 9

The apparatus of claim 5 wherein said means for spectrum analyzing the separated light includes means for spectrum analyzing the separated light of the first polarization.

Claim 10

The apparatus of claim 5 wherein said source means includes a source of white lIght for producing said beam of light of selected bandwidth.