Abstract: An apparatus for processing auscultation signals, e.g. embedded in an electronic stethoscope with a digital readout of an estimated heart rate. The apparatus comprises a bias processor for receiving an auscultation signal and providing a biased auscultation signal; said bias processor comprising an envelope detector and an estimator for calculating a signal representative of the beat frequency of the auscultation signal. In one aspect the information in the biased auscultation signal that is in conformity with the repeated information in the auscultation signal is enhanced. This may e.g. be done by calculating the conformity between the biased auscultation and at least a part of the biased auscultation signal. In another aspect of the invention the auscultation signal is biased by means of A-weighing. Preferably the two aspects of the invention are combined.

Abstract: An electronic stethoscope having a vibration transducer, an amplifier, a headphone arrangement, and at least one digital filter for establishing at least one impulse transfer function corresponding to at least one acoustic stethoscope type. Thus, the signals heard will correspond to those learned, and thereby the advantages of greater amplification and elimination of noise sources may be fully utilized. The ability to compensate for an individual doctor's hearing loss is enabled. Furthermore, with stereoscopic embodiments, sound frequency distributions can be transformed to spatial or temporal sound distributions perceivable by the user facilitating, for example, the detection of heart murmurs and the taking of blood pressure.

Abstract: A method of processing a signal representing an input sound signal is disclosed. The signal is divided in time into a plurality of signal segments, each having an individual duration of time. The signal segments are processed into an output signal of successive signal segments in such a way that at least one, preferably all, of the signal segments are repeated immediately and successively at least once in the output signal. Each signal segment is established in such a way that the duration of time of a majority, preferably all, of the signal segments is less than 60 ms. Thus, a sound signal can be reduced in speed by doubling the number of short cycles.

Abstract: Accelerometers frequently use piezoelectric elements which are subjected to compression or displacement, however rarely to bending, because asymmetries usually appear, which create signals from undesired influences as well. According to the invention this is avoided in a very symmetric construction with a number of mechanically biased bending elements (2) in the same plane, which are only supported at the ends and at the midpoints, where the electrical connections are also made.

Abstract: An electronic stethoscope consisting of a transducer, an amplifier and a headphone will be better adapted to the habits of use of doctors when it is supplied with filters which mimic the transfer function of acoustic stethoscopes. Thus, the signals heard will correspond to those learnt, and thereby the advantages of greater amplification and elimination of noise sources may be fully utilized. Hence there is a possibility for extended digital signal processing which may furthermore compensate for the hearing loss of each individual doctor.

Abstract: A method and an apparatus for determining the content of a constituent of blood of an individual are disclosed. In the method a whole blood stream is extracted from a blood vessel of said individual, the stream being directed through a path defining a substantially non-varying flow-through area wherein is provided a flow-through measuring cuvette including opposite first and second optical transparent surface parts defining an optical transmission path of the order of 0.5-2.0 mm. The whole blood stream flowing through the measuring cuvette is irradiated by irradiating the first optical transparent surface part of the measuring cuvette with multi-wavelength near infrared light. The near infrared absorption spectrum is detected and the content of the constituent is quantified on the basis of the detected near infrared absorption data. The method is particularly suited for measuring constituents of whole blood in an extracorporeal loop, for example in hemodialysis.

Abstract: An apparatus for measuring the cardiac valve function of a person by analyzing an acoustic signal from the heart. The acoustic signal is synchronized with the electrocardiographic signal obtained from the heart. In order to improve the signal-to-noise ratio of the input electrocardiographic signal, the mains-synchronous noise is subtracted from the input electrocardiographic signal. Before analysis of the acoustic signal, a weighting is performed, compensating for individual differences in, in particular, the layer of body fat.