Otto E. Herrmann

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The continuous real time reduction of baseline wander is a considerable problem in electrocardiography during exercises. Our solution consists of spectral filtering. The legitimacy of high-pass filtering of the ECG by means of digital linear phase filters with a low cut-off frequency as high as the heart rate is shown. The specifications of these filters(More)
An algorithm for switchbox routing, called PACKER, is presented. In an initial phase, the connectivity of each net is established in a fast way without taking the other nets into account. In general this will give rise to conflicts (short circuits). In the second stage the conflicts are removed iteratively using Connectivity preserving local transformations(More)
High quality sound reproduction by loudspeakers is increasingly problematic if the dimensions of the loudspeaker decrease. To produce enough power, large diaphragm excursions are needed which give rise to significant distortions especially at very low frequencies. Instead of improving the mechanical construction of the transducer we apply a feedforward(More)
The horn loudspeaker suffers from producing high distortions. Based on an physical model an equivalent lumped parameter circuit is determined for a horn loaded compression driver. From the nonlinear differential equation of this circuit, a compensation algorithm is implemented on a Digital Signal Processor (DSP) for reducing nonlinear distortion caused by(More)
Ideal loudspeakers produce acoustic waves, which are a linear transformation of the electrical input signal. In reality loudspeakers do produce nonlinear distortion as well. This paper presents a method to compensate this distortion in real-time by nonlinear digital signal processing, implemented on a Digital Signal Processor (i. e. the TMS320C30 DSP).(More)
Based on a simpliied nonlinear lumped element model of the electrodynamic loudspeaker in either a closed or a vented cabinet, a new nonlinear controller is derived, simulated and implemented on a DSP. The Volterra series expansion , a well known functional expansion to model nonlinear systems, is used to estimate the nonlinear parameters from distortion(More)
251 fits are possible if the Gaussians are less constrained, that is, if more of their characteristics (amplitude, position, and width) are used. This is demonstrated in Table I. For the first example, the position of the Gaussians was held at the extrema of sin(2t), as done in [1], but the remaining parameters were adjusted to minimize the squared error.(More)