Abstract: A method executable by a computer processor is provided for determining stability of non-linear radio frequency (RF) circuit. The method includes identifying key devices of the RF circuit which open feedback loops when turned off; defining a generalized Bode's return ratio matrix with respect to the key devices over a range of small signal frequencies at a large signal operating point; determining stability margins for gain and phase of the RF circuit based on eigenvalues of the Bode's return ratio matrix; and determining overall stability of RF circuit using the Nyquist locus of a normalized determinant function based on the determinant of the generalized Bode's return ratio matrix.

Abstract: An adjunctive ultrasound mammography system and associated methods use an adjunctive ultrasound display configured for quick, intuitive, interactive viewing of volumetric ultrasound scans, displayed near a conventional x-ray mammogram display. Preferred navigations among a thick-slice image array, a selected enlarged thick-slice image, and planar ultrasound views are described, including a mode in which the planar ultrasound views are updated in real time as a cursor is moved across an active thick-slice image. In one example the thick-slice images are inverted prior to display, with non-breast areas of the image preferably segmented out and reset to dark. The inverted thick-slice images are of more familiar significance to radiologists as they are more like conventional x-ray mammograms and allow benign features to be more easily dismissed as compared to non-inverted thick-slice images.

Abstract: A method of operating a data processing system to generate a jitter-injected signal from an input signal that is a function of time is disclosed. A time offset corresponding to a first time is generated according to a jitter specification that specifies the offset as a function of time. The jitter-injected signal at the first time is generated by evaluating the input signal at a time equal to a sum of the time offset and the first time. If the jitter specification only provides offsets at signal crossing times, interpolation is used to derive time offsets at non-signal crossing times.

Abstract: An adjunctive ultrasound mammography system and associated methods use an adjunctive ultrasound display configured for quick, intuitive, interactive viewing of volumetric ultrasound scans, displayed near a conventional x-ray mammogram display. Preferred navigations among a thick-slice image array, a selected enlarged thick-slice image, and planar ultrasound views are described, including a mode in which the planar ultrasound views are updated in real time as a cursor is moved across an active thick-slice image. In one example the thick-slice images are inverted prior to display, with non-breast areas of the image preferably segmented out and reset to dark. The inverted thick-slice images are of more familiar significance to radiologists as they are more like conventional x-ray mammograms and allow benign features to be more easily dismissed as compared to non-inverted thick-slice images.

Abstract: Methods for analyzing circuit distortion based on contributions from separate circuit elements are presented. Local approximations that do not require high-order derivatives of device models are developed near an operating point for calculating distortion summaries including compression summaries and second-order intermodulation (IM2) distortion summaries.

Abstract: A causal impulse response function is calculated from a truncated spectrum by extending the real part of the spectrum beyond the truncation frequency and computing the imaginary part with the Hilbert transform to enforce causality. The out of band extrapolation is optimized to reduce the discrepancy between the computed and the original imaginary part in the in band frequency range so that the causal impulse response accurately represents the original spectrum. The technique can be applied to spectral with the delay phase subtracted to enforce delay causality. The Hilbert transform may be employed to maintain causality in S-parameter passivity violation correction. At frequencies where violation happens, the S-parameter matrix is scaled down by the inverse of the magnitude of the largest eigenvalue. Magnitudes at other frequencies are unchanged. An additional phase calculated by the magnitude phase Hilbert transform is added to the scaled spectrum to maintain the causality.

Abstract: An adjunctive ultrasound mammography system and associated methods are described, comprising a scanning apparatus for facilitating standardized, repeatable breast ultrasound scans, and further comprising an adjunctive ultrasound display apparatus configured for fast, intuitive viewing of adjunctive ultrasound data concurrently with x-ray mammogram information. In one preferred embodiment, thick-slice ultrasound images are displayed near an x-ray mammogram such that a screening radiologist can quickly view the thick-slice images for assistance in interpreting the x-ray mammogram. Methods for concurrently acquiring and displaying vibrational resonance image (VDI) data are described. Computer-aided diagnosis (CAD) algorithms that incorporate acoustically-based feature vectors are described, the feature vectors including lateral shadow metrics, vertical shadow metrics, posterior enhancement metrics, and VDI-based metrics.

Abstract: A pertubative approach based on the Born approximation resolves weakly nonlinear circuit models without requiring explicit high-order device derivatives. Convergence properties and the relation to Volterra series are discussed. According to the disclosed methods, second and third order intermodulation products (IM2, IM3) and intercept points (IP2, IP3) can be calculated by second and third order Born approximations under weakly nonlinear conditions. A diagrammatic representation of nonlinear interactions is presented. Using this diagrammatic technique, both Volterra series and Born approximations can be constructed in a systematic way. The method is generalized to calculate other high-order nonlinear effects such as IMn (nth order intermodulation product) and IPn (nth order intermodulation intercept point). In general, the equations are developed in harmonic form and can be implemented in both time and frequency domains for analog and RF circuits.

Abstract: An adjunctive ultrasound mammography system and associated methods are described comprising an adjunctive ultrasound display configured for quick, intuitive, interactive viewing of data derived from volumetric ultrasound scans, the data being displayed near a conventional x-ray mammogram display. Preferred embodiments for navigating among a thick-slice image array, a selected enlarged thick-slice image, and planar ultrasound views are described, including a preferred embodiment in which the planar ultrasound views are updated in real time as a cursor is moved across an active thick-slice image. In one preferred embodiment the thick-slice images are inverted prior to display, with non-breast areas of the image preferably segmented out and reset to dark. The inverted thick-slice images are of more familiar significance to radiologists having years of expertise in analyzing conventional x-ray mammograms.

Abstract: An adjunctive ultrasound mammography system and associated methods are described comprising an adjunctive ultrasound display configured for quick, intuitive, interactive viewing of data derived from volumetric ultrasound scans, the data being displayed near a conventional x-ray mammogram display. Preferred embodiments for navigating among a thick-slice image array, a selected enlarged thick-slice image, and planar ultrasound views are described, including a preferred embodiment in which the planar ultrasound views are updated in real time as a cursor is moved across an active thick-slice image. In one preferred embodiment the thick-slice images are inverted prior to display, with non-breast areas of the image preferably segmented out and reset to dark. The inverted thick-slice images are of more familiar significance to radiologists having years of expertise in analyzing conventional x-ray mammograms.

Abstract: An adjunctive ultrasound mammography system and associated methods are described, comprising a scanning apparatus for facilitating standardized, repeatable breast ultrasound scans, and further comprising an adjunctive ultrasound display apparatus configured for fast, intuitive viewing of adjunctive ultrasound data concurrently with x-ray mammogram information. In one preferred embodiment, thick-slice ultrasound images are displayed near an x-ray mammogram such that a screening radiologist can quickly view the thick-slice images for assistance in interpreting the x-ray mammogram. Methods for concurrently acquiring and displaying vibrational resonance image (VDI) data are described. Computer-aided diagnosis (CAD) algorithms that incorporate acoustically-based feature vectors are described, the feature vectors including lateral shadow metrics, vertical shadow metrics, posterior enhancement metrics, and VDI-based metrics.

Abstract: Methods for analyzing circuit distortion based on contributions from separate circuit elements are presented. Local approximations that do not require high-order derivatives of device models are developed near an operating point for calculating distortion summaries including compression summaries and second-order intermodulation (IM2) distortion summaries.

Abstract: Ultrasound mammography in which an automated transducer scans the patient's breast to generate many images of thin slices that are processed into few images of thick slices that can be displayed simultaneously for practical rapid assessment of the breast. The thin-slice images can be acquired by a technician so that a physician need only spend time in assessing the few displayed thick-slice images and, possibly, only a few of the thin-slice images that might match a suspected anomaly indicated in the thick-slice images. Computer-aided detection or diagnosis (CAD) can be performed on the images and resulting mark and/or other information can be displayed as well. Vibration images can be obtained as well and similarly processed and displayed to highlight abnormalities or for other reasons.

Abstract: A causal impulse response function is calculated from a truncated spectrum by extending the real part of the spectrum beyond the truncation frequency and computing the imaginary part with the Hilbert transform to enforce causality. The out of band extrapolation is optimized to reduce the discrepancy between the computed and the original imaginary part in the in band frequency range so that the causal impulse response accurately represents the original spectrum. The technique can be applied to spectral with the delay phase subtracted to enforce delay causality. The Hilbert transform may be employed to maintain causality in S-parameter passivity violation correction. At frequencies where violation happens, the S-parameter matrix is scaled down by the inverse of the magnitude of the largest eigenvalue. Magnitudes at other frequencies are unchanged. An additional phase calculated by the magnitude phase Hilbert transform is added to the scaled spectrum to maintain the causality.

Abstract: An adjunctive ultrasound mammography system and associated methods are described in which an ultrasound image being displayed near an x-ray mammogram image may be superimposed thereon or thereunder by a user for facilitating rapid comprehension of breast structures and detection of abnormalities therein. In one preferred embodiment, the x-ray mammogram image corresponds to a standard x-ray mammogram view, and the ultrasound image is a thick-slice image representing a thick-slice or slab-like portion of the breast volume substantially parallel to that standard x-ray mammogram view. In another preferred embodiment, the user is permitted to manually manipulate the registration of the ultrasound image with the x-ray mammogram image. It has been found that the manual registration process, which involves manual vernier adjustments responsive to perceived registration differences, can rapidly increase the radiologist's perception of the breast structures being displayed by both component images.

Abstract: A pertubative approach based on the Born approximation resolves weakly nonlinear circuit models without requiring explicit high-order device derivatives. Convergence properties and the relation to Volterra series are discussed. According to the disclosed methods, second and third order intermodulation products (IM2, IM3) and intercept points (IP2, IP3) can be calculated by second and third order Born approximations under weakly nonlinear conditions. A diagrammatic representation of nonlinear interactions is presented. Using this diagrammatic technique, both Volterra series and Born approximations can be constructed in a systematic way. The method is generalized to calculate other high-order nonlinear effects such as IMn (nth order intermodulation product) and IPn (nth order intermodulation intercept point). In general, the equations are developed in harmonic form and can be implemented in both time and frequency domains for analog and RF circuits.

Abstract: An adjunctive ultrasound mammography system and associated methods are described in which an ultrasound image being displayed near an x-ray mammogram image may be superimposed thereon or thereunder by a user for facilitating rapid comprehension of breast structures and detection of abnormalities therein. In one preferred embodiment, the x-ray mammogram image corresponds to a standard x-ray mammogram view, and the ultrasound image is a thick-slice image representing a thick-slice or slab-like portion of the breast volume substantially parallel to that standard x-ray mammogram view. In another preferred embodiment, the user is permitted to manually manipulate the registration of the ultrasound image with the x-ray mammogram image. It has been found that the manual registration process, which involves manual vernier adjustments responsive to perceived registration differences, can rapidly increase the radiologist's perception of the breast structures being displayed by both component images.

Abstract: An adjunctive ultrasound mammography system and associated methods are described in which an ultrasound image being displayed near an x-ray mammogram image may be superimposed thereon or thereunder by a user for facilitating rapid comprehension of breast structures and detection of abnormalities therein. In one preferred embodiment, the x-ray mammogram image corresponds to a standard x-ray mammogram view, and the ultrasound image is a thick-slice image representing a thick-slice or slab-like portion of the breast volume substantially parallel to that standard x-ray mammogram view. In another preferred embodiment, the user is permitted to manually manipulate the registration of the ultrasound image with the x-ray mammogram image. It has been found that the manual registration process, which involves manual vernier adjustments responsive to perceived registration differences, can rapidly increase the radiologist's perception of the breast structures being displayed by both component images.

Abstract: An adjunctive ultrasound mammography system and associated methods are described in which an ultrasound image being displayed near an x-ray mammogram image may be superimposed thereon or thereunder by a user for facilitating rapid comprehension of breast structures and detection of abnormalities therein. In one preferred embodiment, the x-ray mammogram image corresponds to a standard x-ray mammogram view, and the ultrasound image is a thick-slice image representing a thick-slice or slab-like portion of the breast volume substantially parallel to that standard x-ray mammogram view. In another preferred embodiment, the user is permitted to manually manipulate the registration of the ultrasound image with the x-ray mammogram image. It has been found that the manual registration process, which involves manual vernier adjustments responsive to perceived registration differences, can rapidly increase the radiologist's perception of the breast structures being displayed by both component images.

Abstract: An adjunctive ultrasound mammography system and associated methods are described comprising an adjunctive ultrasound display configured for quick, intuitive, interactive viewing of data derived from volumetric ultrasound scans, the data being displayed near a conventional x-ray mammogram display. Preferred embodiments for navigating among a thick-slice image array, a selected enlarged thick-slice image, and planar ultrasound views are described, including a preferred embodiment in which the planar ultrasound views are updated in real time as a cursor is moved across an active thick-slice image. In one preferred embodiment the thick-slice images are inverted prior to display, with non-breast areas of the image preferably segmented out and reset to dark. The inverted thick-slice images are of more familiar significance to radiologists having years of expertise in analyzing conventional x-ray mammograms.