Abstract: A shockwave generator for extracorporeal lithotripsy has a housing filled with an acoustic propagation medium, through which shockwaves propagate, and in which an ultrasound applicator is disposed for locating a calculus to be treated. The ultrasound applicator has components which may be damaged if traversed by shockwaves. At least a portion of the ultrasound applicator in which these components are disposed is therefore acoustically shielded with a substance having an acoustic impedance substantially differing from the acoustic impedance of the propagation medium, so that essential parts of the shockwaves are reflected thereby and thus the non-reflected parts do not reach the shielded portion of the ultrasound applicator with sufficient energy to damage the compartments.

Abstract: Phased-array apparatus has a number of ultrasonic transducer elements (E1 to E64) to which are associated delay line elements (M1, T1 to M64, T64, W1-1, W1-2, N1 to W16-1, W16-2, N16; W1 to W16; VL1 to VL64, VR1 to VR16) to provide reception. In order that the control angle may be adjusted with high accuracy, according to the inventive principles delay line elements are provided for the received signals with a short and with a long delay, and several adjacent channels are combined for signal processing. Due to this arrangement, economical constructions of embodiments of the invention are realized.

Abstract: An ultrasound apparatus permitting dynamic variation of the position of the reception focus of a prescribable number of ultrasound transducer elements has a reception channel including a time-delay circuit for the received ultrasound echo signal following every ultrasound transducer element. For switching between different, prescribed time-delay values (T.sub.1, T.sub.2, . . . T.sub.n), the time-delay circuit is connected to a control device. A part of the time-delay circuit is redundantly designed, so that first and a second sub-circuits for forming the time-delayed ultrasound echo signal are present. A dissolve circuit is provided which causes the second sub-circuit to be faded in the reception channel when the first sub-circuit, in a blanked condition, is switched to a different time-delay value (T.sub.1, T.sub.2, . . . T.sub.n), and vice versa, by a control device. Significant time is thus saved when switching between the different focus positions of the ultrasound apparatus.

Abstract: In the exemplary embodiments, the apparatus comprises: an ultrasonic transducer arrangement; a drive arranged to pivotably displace the transducer arrangement within a predetermined angular range; an actual-value generator for supplying a signal (F.sub.I (.rho.) dependent upon the angular position of the transducer arrangement within the said range; a desired-value generator for supplying a signal (F.sub.S (.rho.)) representing a desired angular position of the transducer arrangement within the said range; and a control for controlling the drive in dependence upon such signals from the actual-value and desired-value generators. The actual-value and desired-value generators are adapted to supply respective signals having the same or similar forms over a relatively large signal range within the said range.

Abstract: A bipolar cutting electrode for high-frequency surgery having at least two mutually insulated and high-frequency voltage conductive metal portions which are at a fixed spacing relative to each other. The metal portions are metal tips which are located within the effective zone of the electrode in series in the cutting direction. When employing more than two metal tips, these should be positioned in a row extending along a semi-circular arc which may also be formed, for example, in a lancette-shape.