Abstract: A system for filtering stochastic signals as embodied in stress test systems for measuring electrocardiographic (ECG) activity in response to exercise employs a bidirectional Infinite Impulse Response (IIR) filtering process over a predetermined window on a digitized version of an ECG signal to eliminate noise up to the 0.67 Hz frequency range. To eliminate phase shifting distortion in the ECG signal, the IIR filter is applied in a first direction over a predetermined window of the ECG and then applied in a second direction opposite the first direction segment over the identical window. In this manner the phase shift distortion normally associated with IIR filters is completely eliminated and superior bandwidth (as compared to FIR filters) is obtained. The response is achieved fast enough to be used in real time purpose.

Abstract: A system for filtering stochastic signals as embodied in stress test systems for measuring electrocardiographic (ECG) activity in response to exercise employs a bidirectional Infinite Impulse Response (IIR) filtering process over a predetermined window on a digitized version of an ECG signal to eliminate noise up to the 0.67 Hz frequency range. To eliminate phase shifting distortion in the ECG signal, the IIR filter is applied in a first direction over a predetermined window of the ECG and then applied in a second direction opposite the first direction segment over the identical window. In this manner the phase shift distortion normally associated with IIR filters is completely eliminated and superior bandwidth (as compared to FIR filters) is obtained. The response is achieved fast enough to be used in real time purpose.

Abstract: A method and apparatus for dynamically estimating the ST segment of a rate varying electrocardiogram by comparing the result yielded from a mathematical relationship between calculated beat averages and a predetermined standard. Typically a table of known heartbeats is made from which means for estimating are created. An average of beat to beat intervals is compared with the means for estimating and the length of the ST segment for any particular beat is derived making it possible to dynamically alter ST segment length for any given heartrate.

Abstract: A system for filtering stochastic signals as embodied in stress test systems for measuring electrocardiographic (ECG) activity in response to exercise employs a bidirectional Infinite Impulse Response (IIR) filtering process over a predetermined window on a digitized version of an ECG signal to eliminate noise up to the 0.67 Hz frequency range. To eliminate phase shifting distortion in the ECG signal, the IIR filter is applied in a first direction over a predetermined window of the ECG and then applied in a second direction opposite the first direction segment over the identical window. In this manner the phase shift distortion normally associated with IIR filters is completely eliminated and superior bandwidth (as compared to FIR filters) is obtained. The response is achieved fast enough to be used in real time purpose.

Abstract: The invention discloses a method and an apparatus for creating optical disc recordings by forming pits having ideal shapes. These ideally shaped pits are improvements in the technology of disc mastering, due to the manufacturing and data playback advantages that are inherent in the ideally shaped pits. A disc substrate has a very thin partially reflective layer applied to the surface of the optical disc upon which data will be recorded. The substance used to make the partially reflective layer is normally considered opaque in more commonly occurring thicknesses. However, the partially reflective layer, is created to be so extremely thin that it becomes partially optically transparent. The partially reflective layer then has spin coated, thereon, an optically active lamina to enable the recording of data on the disc by laser means in the form of pits.

Abstract: A frequency domain signal processing and analysis method and apparatus displays, plots and makes measurements upon electrocardiographic signals (ECG) recorded from the body surface. Both the graphic plots and the numeric parameters measured reveal abnormalities of electrical conduction within the heart thought to be important in the identification of patients at risk of serious disturbances of heart rhythm including sudden death. The invention employs Fourier analysis of short overlapping segments of ECG signal to create a three dimensional map ("spectrocardiogram") whose axes are time, fequency and power thus disclosing changes in the frequency content of the ECG signal over short intervals of time.

Abstract: The invention discloses a simplified four step process for making an optical disc master or alternatively a WORM disc by first making or obtaining a transparent polymer disc with a tracking groove of desired geometry molded therein, then spin coating an optically active lamina on the grooved side of the disc, then recording data on said polymer disc with groove controlled and tracked laser means by ablating active lamina, forming pits, the shape of which is determined by the groove geometry and finally depositing a conductive and reflective lamina over the pitted active lamina. To change the OD master to an OD WORM, a protective cover is added to the electrically conductive and optically reflective lamina.

Abstract: A time saving automatic screening system for detection, measurement, analysis and plotting of electrocardiographic (ECG) signals employing arrhythmia analysis programs on long term ambulatory (Holter) recordings to assess the ECG signals and categorize the recorded data as either artifact, ventricular ectopic, superventricular ectopic, unknown or normal and to calculate a level of confidence that the category as chosen is a correct assessment. A system is disclosed that thresholds the occurrences of each category as well as the level of confidence to determine if significant abnormalities have occurred in the recording process, the hearts arrhythmia, or the heartbeat morphology. The method and apparatus disclosed make it possible to identify and screen out entire long term (Holter) ECG recordings containing no significant abnormalities in the hearts arrhythmia or the beat morphology.

Abstract: The invention is a sealed optical tape cassette. Sealed means is employed to pull optical tape across a mobile recording bridge situated behind a transparent window. Bridge is operated upon by a pair of sealed internal/external pins to control tape tilt, focus and tracking of a light beam from a spinning optical head in a recorder/player to a desired point on the optical tape.

Abstract: A micro cassette recorder-player is disclsoed having capactity for increased signal-to-noise ratio by utilizing a mobile capstan which pulls tape out of a micro cassette and across an enlarged head placed distal to and shielded from all electric motors, solenoids, and inductors which typically create spurious electric and magentic flux fields that traditionally diminish S/N.