Abstract: An isolation transformer arrangement has an isolation transformer having magnetically coupled primary and secondary windings, one of which is formed of at least one planar conductive run formed on an associated face of an insulating substrate of a printed circuit board and the other is formed of a number of turns of an insulated wire conductor. The printed circuit board also has one or more discreet electric components arranged in two electrically separate circuits each circuit connectable to a respective one of the primary and the secondary windings of the isolation transformer. The insulation of the wire conductor winding provides a desired level of electrical isolation between the circuits necessary for use in medical equipment.

Abstract: An interface unit for an electrophysiology measurement system has a number of externally accessible electrical connectors, each connector for releasably mating with one of a number of wires from a combination of catheter-mounted sensors. A fixed configuration connector is provided in a fixed coupling to the connectors and is couplable to an electrophysiology monitoring system. The unit further has a signal generator, such as a suitably programmed EEPROM in combination with appropriate electrical circuitry mounted on an internally located printed circuit board, which generates an output signal containing information particular to and originating from the unit for use by the electrophysiology monitoring system.

Abstract: An interface unit for establishing an electrical coupling of a number of sensor wires from a combination of catheters with a number of electrical signal channels of a electrophysiological monitoring system has a number of electrical contacts for coupling individual wires with individual channels. Each contact is releasably engageable with an individual wire. A number of overlays which are removably locatable at the outer surface and are attached to the housing of the unit by binding rings. Each overlay carries on a face thereof a visible indication of a different one of a number of stored wire/contact configurations. The configurations are organized such that contacts for receiving wires from a same catheter are grouped together and the indication is formed as visibly differentiated regions, each de-marking a different grouping.

Abstract: An interface unit for an electrophysiology measurement system has a number of externally accessible electrical connectors, each connector for releasably mating with one of a number of wires from a combination of catheter-mounted sensors. A fixed configuration connector is provided in a fixed coupling to the connectors and is couplable to an electrophysiology monitoring system. The unit further has a signal generator, such as a suitably programmed EEPROM in combination with appropriate electrical circuitry mounted on an internally located printed circuit board, which generates an output signal containing information particular to and originating from the unit for use by the electrophysiology monitoring system.

Abstract: An interface unit for establishing an electrical coupling of a number of sensor wires from a combination of catheters with a number of electrical signal channels of a electrophysiological monitoring system has a number of electrical contacts for coupling individual wires with individual channels. Each contact is releasably engageable with an individual wire. A number of overlays which are removably locatable at the outer surface and are attached to the housing of the unit by binding rings. Each overlay carries on a face thereof a visible indication of a different one of a number of stored wire/contact configurations. The configurations are organized such that contacts for receiving wires from a same catheter are grouped together and the indication is formed as visibly differentiated regions, each de-marking a different grouping.

Abstract: In a device for monitoring measurement electrodes, attached to a patient in order to pick up physiological measurement signals, and a neutral electrode and associated leads at the same time as physiological measurement signals are picked up, each measurement electrode is connected to an input terminal on its associated measurement amplifier. A test signal generator is arranged to generate a pure AC signal, without any direct current component, across the neutral electrode attached to a patient during the pickup of measurement signals.

Abstract: A lamp (34) for a refrigerator or freezer cabinet is located forwardly and above a horizontal edge (38) of an access opening (16) to a storage space (12) for goods in the cabinet. The lamp (34) illuminates the space (12) through the access opening by means of a reflector (36). The reflector (36) includes a cylindrical part (52) having a semi-elliptical cross-sectional shape. A concave side of the cylindrical part (52) faces the access opening (16). The lamp has a filament (42) which shines in the shape of a line (44) running parallel to the edge (38) and through one (42) of the focal points of the ellipse. The other focal point (58) of the ellipse is located quite close to and outside the edge (38), so that the light from the filament (42) first is reflected by the cylindrical part (52) of the reflector (36) and then passes through the other focal point (58) on its way into the space (12).

Abstract: In a device for monitoring measurement electrodes, attached to a patient in order to pick up physiological measurement signals, and a neutral electrode and associated leads at the same time as physiological measurement signals are picked up, each measurement electrode is connected to an input terminal on its associated measurement amplifier. A test signal generator is arranged to generate a pure AC signal, without any direct current component, across the neutral electrode attached to a patient during the pickup of measurement signals.

Abstract: A device for filtering ECG signals has an A/D converter and a filter unit connected to the converter's output. The filter unit includes a filter, or a combination of filters with a non-linear phase response such that signals with frequencies in the passband of the filter, or the combination of filters, are delayed more than signals with frequencies in the transition band between the passband and the suppressed frequency band of the filter, or the combination of filters. A method for producing an FIR filter, with a phase response opposite to the phase response of a filter for filtering out DC components, or an IIR filter, suitable for use in the above-described device, is also disclosed in which the impulse response from the filter for filtering out DC components and low-frequency components or the IIR filter is reversed in time and sampled. The sampled values are then used for determining coefficients for the FIR filter.

Abstract: In a method for enhancing the signal-to-noise ratio of ECG signals, A/D-converted signals from a number of cardiac cycles are time-synchronized to form a signal ensemble, and the correlation between the signals in the ensemble is determined in time intervals, comprising at least two samples, during at least a part of the cardiac cycles. A device for enhancing the signal-to-noise ratio of ECG signals, includes circuitry for recording, A/D-converting and other processing of the ECG signals. A synchronization unit is arranged to time-synchronize the signals from a plurality of cardiac cycles to form a signal ensemble, and a calculator unit controlled by a window unit determines the correlation between the signals in the ensemble in time intervals, comprising at least two samples, during at least a part of the cardiac cycles.

Abstract: A device for eliminating ringing in filtered ECG signals includes an analog-to-digital for converting the ECG input signals into a series of digital values, and a filter unit connected to the output of the analog-to digital converter. The filter unit includes a recursive IIR-filter and a subsequent allpass filter with a phase shift which is equal to twice the phase shift of the IIR filter. The allpass filtering is performed time-reversed with respect to the IIR filtering. In a method for producing an allpass filter, for use in the above device, having a phase shift which is equal to twice the phase shift of an IIR filter, the IIR filter having zero points situated on the unity circle in the Z-plane, the zero points of the IIR filter are replaced by new zero points obtained by reflecting the poles of the filter in the unity circle in the Z-plane.

Abstract: A boxlike body (10) with a rear wall (12) and four side walls (14) is brought into a fixture (34) with the free edges (22) of the side walls pointing downwards. The walls of the body are filled with insulating powder by blowing the powder into the rear wall (12) by gaseous medium of a first pressure. The powder is then packed by gaseous medium of a second pressure, which is higher than the first pressure, being let into the rear wall. During the filling and packing the media is let out via a filter element (24) arranged at the free edges (22) of the side walls. After the filling and packing the media is evacuated from the walls through the filter element (24). The body can then be used as a so-called vacuum insulation in a refrigerator or freezer.

Abstract: In a method and apparatus for processing ECG signals for the purpose of detecting low-amplitude signal structures hidden in noise in the ECG signal, the ECG signals, number of cardiac cycles are analog-to-digital converted, and QRS complexes in the converted signals are detected. The signals from at least two cardiac cycles are cross-correlated, and the correlation between these signals in time intervals which comprise at least the time intervals of the two samples is determined. An output quantity representing the degree of correlation is thus obtained, the magnitude of this quantity designating the amplitude of the signal structure in question. This magnitude can then be analyzed to determine if, and where in the signal, the signal structure arises.

Abstract: Method and device for filtering out baseline fluctuations from an electrocardiogram. It is known to provide a high pass filter for filtering out baseline fluctuations from an electrocardiogram, the lower cut off frequency of a high pass filter is at a value below the frequencies which are characteristic of the heart signals at the lowest possible heart rate. In order to increase the effectiveness of the baseline filtering, it is provided that in a device (4) the current heartbeat rate is determined from the electrocardiogram and, in dependence thereupon, the lower cut off frequency of the filter (2) is altered in such a manner that the lower cut off frequency is increased in the case of an increasing heartbeat rate and is decreased in the case of a decreasing heartbeat rate.

Abstract: Apparatus for filtering out baseline fluctuations from physiological measurement signals. The apparatus comprises a first nonrecursive low-pass filter with a downstream stage for the reduction of the sampling rate, a second nonrecursive filter connected thereto, a subsequent interpolation stage to increase the sampling rate and a subtraction stage, in which the baseline fluctuations retained by the low-pass filtering are subtracted from the measurement signals affected by baseline fluctuations. To reduce the number of computing operations to be performed in the course of the sampling filtering, the first low-pass filter comprises a recursive filter.

Abstract: Circuit arrangement for the processing of physiological measurement signals. In a known circuit arrangement, each one of a plurality of electrodes for picking up physiological measurement signals connects with a first input connection of an input amplifier associated with the pertinent electrodes; the input amplifiers connect, at their respective second input connections, with a common reference potential connection. To check the functional capability of the input amplifiers, a calibration pulse generator connects on the output side with one of the electrodes and the reference potential connection. In addition, to check the electrodes (1, 2, 3) and their supply lines, an additional amplifier (24) connects, by its input, with the reference potential connection (7) and, at its output, with an additional electrode (25) on the patient.

Abstract: A method for analog-to-digital conversion includes the steps of applying a first transfer function to the input signal and amplifying the input signal by a defined gain factor to obtain an edited signal, subject chronologically successive samples of both the input signal and the edited signal to analog-to-digital conversion and thereby obtaining digital data having a defined number of bits corresponding to the input signal and digital data having a defined number of bits corresponding to the edited signal, multiplying the digital data corresponding to the input signal by a defined factor equal to the gain factor, applying a second transfer function to the digital data corresponding to the input signal by digital filtering, and undertaking calculations on the signals obtained in this manner to obtain a final analog-to-digital conversion result. An apparatus operating according to this method is also disclosed.

Abstract: A method for analog-to-digital conversion of a chronologically changing, analog input signal includes the steps of forming an edited signal from an input signal by subjecting the input signal to a first transfer function and amplifying the result by a defined gain factor, sampling the input signal and the edited signal and subjecting the sampled signals to analog-to-digital conversion to obtain first and second digital data respectively corresponding to the edited signal and the input signal. The number of bits in each of the first and second digital data determines the dynamic range of the analog-to-digital conversion. The first digital data, corresponding to the input signal, are multiplied by a defined factor equal to the defined gain factor. If a transgression of the dynamic range in the analog-to-digital conversion has not occurred, the final analog-to-digital conversion result is calculated making use of the second digital data corresponding to the edited signal.

Abstract: A holographic system for recording movements of body surfaces of a patient characterized by a source of coherent light projecting on the body surface to create an object wave and having a portion of the light as a reference wave, a film carrier for photographic film disposed to simultaneously record the object and reference waves as a hologram and switching devices which are activated by a transmitter device sensing cardiac activity for double pulse switching of the source at predetermined intervals so that the two separate holograms of the body surface are recorded with each hologram being at a different time interval of the movement of the body. The present invention enables the two holograms which are recorded on the film to be recorded at given points in a cardiac activity of the patient such as given points of the EKG cycle of the patient.