Abstract: An intensity stabilized laser including a gain cavity containing a gain medium; and an absorbing cavity containing a nonlinear absorbing medium, wherein the absorbing cavity is located with respect to the gain cavity and the characteristics of the nonlinear absorbing medium are selected so as to provide negative feedback from the absorbing cavity to the gain cavity during operation of the laser to thereby control the gain of the gain cavity.

Abstract: A system of generating a spectral phonocardiogram which summarizes time-dependent changes in the heart sounds throughout the heart cycle. The system is based on the projection of spectral surfaces of the Fourier transform of heart sounds as a function of time and is a useful diagnostic tool both for a cardiologist and a general practitioner. Permanent copies of the spectral phonocardiograms can provide useful records for monitoring the development of heart disease in a given individual. The system provides a useful means for rapid screening of large groups of people for heart disease by non-specialists in cardiology. A variant of the system provides automated computer diagnosis of the probable nature of the heart disease.

Abstract: A system of generating a spectral phonocardiogram which summarizes time-dependent changes in the heart sounds throughout the heart cycle. The system is based on the projection of spectral surfaces of the Fourier transform of heart sounds as a function of time and is a useful diagnostic tool both for a cardiologist and a general practitioner. Permanent copies of the spectral phonocardiograms can provide useful records for monitoring the development of heart disease in a given individual. The system provides a useful means for rapid screening of large groups of people for heart disease by non-specialists in cardiology. A variant of the system provides automated computer diagnosis of the probable nature of the heart disease.

Abstract: A method and device for compensating for partial hearing loss by converting a time domain signal corresponding to a sound into a series of digital component values in the frequency domain, performing a nonlinear amplitude gain operation in the frequency domain on each of the digital component values and converting the digital component values back into a time domain signal corresponding to the sound with compensation for partial hearing loss.