Abstract: In a method for fractal coding of signals, in which a domain block d is investigated for a range block r to be transmitted from an original signal, so that, after using the calculation rule r*=v·d+b, an approximated range block r* is generated, v·d being a linear function and b being an offset vector, the offset vector b in general has different components b=(b1, b2, . . . , bn) the offset vector b preferably being composed of weighted orthogonal basic functions of an orthogonal transformation.

Abstract: A method is proposed for checking convergence in fractal image coding. In this case, a digitized image is divided into a number of range blocks (R.sub.i, R.sub.i+1) and into a number of domain blocks (D.sub.j, D.sub.k). A similar domain block is determined in relation to each range block. If necessary, in this process a transformation of a domain block is undertaken in order to map the domain block onto a range block. The assignment of the domain block to the range block including the transformation parameters represents the fractal code for the image. A reduced transformation matrix is set up to check convergence of the fractal code. The largest absolute eigenvalue of the transformation matrix is determined approximately. The entire method can be carried out in this case hierarchically. In a first approximation step, at least the row sum norm of each row of the reduced transformation matrix is checked. In further steps, further rows are combined to form square matrices of higher dimension.

Abstract: The process disclosed enables the "time domain aliasing cancellation" method to be extended systematically to larger block overlapping. The boundary conditions which, when using various modified transforms, the analysis and synthesis windows must comply with, can thus be given. The transform series must also be included in the design of each analysis and synthesis window in order to optimize for a given application, because this changes the boundry conditions with which an analysis window function can be determined. Design for analysis and synthesis windows have shown that analysis and synthesis properties obtained by multiple block overlapping are significantly better than those obtained by convential double block overlapping. The systematic method of the invention offers numerous possibilites for optimizing windows in special applications.

Abstract: A signal is divided by windows into successive blocks that overlap at least by 50% and signal sections contained in the blocks are evaluated by analysis windows. The signal sections contained in the blocks are subjected to a transformation which permits sub-sampling with compensation of the aliasing components such as, for example, the "time domain aliasing cancellation" method. The spectra resulting from the transformation are subsequently coded, transmitted, decoded after transmission and changed back to signal sections by re-transformation. The blocks including the signal sections are evaluated by synthesis windows and are joined together in an overlapping fashion. The window functions of the synthesis windows are determined in dependence on the window functions of the corresponding analysis windows in the overlap region.

Abstract: A method of transmitting an audio signal wherein the audio signal is partitioned into successive (in time) blocks by means of time windows, the signal parts contained in the blocks are converted to short-time frequency spectrums by transformation, subsequently the short-time frequency spectrums are coded on the basis of psycho-acoustical masking laws and are transmitted. The received coded signals are decoded, the short-time frequency spectrum signals are brought back into the time domain through re-transformation, and finally the blocks present in the time domain are assembled. Moreover, the blocks are partitioned into sub-blocks and, in case of signal level changes from one block to the other which exceed a predetermined value, the signal parts in the sub-blocks are subjected to a compression prior to transformation and to a complementary expansion after the re-transformation.

Abstract: A method and apparatus for reducing a resonance peak in a piezoelectric transducer for mechanically recording a signal having a band width of several MHz, in particular on a video disk comprising, applying a countercoupling current across terminals of the transducer for counteracting a current flow in the parallel capacitance of the transducer. A circuit of the invention comprises a piezoelectric transducer having two terminals and including in series a characteristic inductance, capacitance, and resistance, and a parallel capacitance characteristic in parallel to the series characteristic, a signal generator for generating the signal to be recorded, a transformer having a primary winding connected to the signal generator and a secondary winding connected to one terminal of the transducer with a symmetrically disposed central ground connected to the secondary winding.

Abstract: An amplifier circuit having a variable transmission factor and an effective transmission frequency band delimited by a lower limit frequency is arranged to enable the value of the lower limit frequency to be varied as a function of a control voltage, by including in the circuit an amplifier member and circuit components defining a feedback path connected between the output of the amplifier and an input thereof which is inverting with respect to the output signals of the amplifier, the components defining the feedback path including an electronically voltage-controllable resistor having a control voltage input and a first frequency dependent impedance connected in parallel with the resistor, and the circuit further including a second frequency dependent impedance connected between the inverting input of the amplifier and a point at the circuit reference potential, and a line for supplying the control voltage to the control voltage input of the controllable resistor.

Abstract: In a circuit for the automatic dynamic compression or expansion of a signal between its input and its output, the circuit presenting a useful signal path connected between its input and its output and connecting a first variable gain member which is electronically controllable for varying the transmission factor between the circuit input and output, the circuit also presenting a branch path connected at one point to the useful signal path and containing a second variable gain member which is electronically controllable for varying the transmission factor exhibited by the branch path, and a control voltage generator for generating a control voltage applied to control the variable gain members for effecting a counterregulation of the transmission factor of the branch path, relative to the transmission factor variation imparted to the useful signal path, there is further provided a combining circuit which receives the output signal from the second variable gain member and a signal proportional to a signal at a p

Abstract: An amplifier circuit whose gain bears a desired relation to a control voltage, including a differential amplifier, a plurality of impedances interconnected between the amplifier terminals and switches interconnected with the impedances and switchable between two states which create two impedance configurations that give the circuit mutually complementary gain vs. control voltage control characteristics.

Abstract: In a circuit for compensating time errors in a television signal and including an electronically controllable delay line in the path of the signal and control signal producing elements in a control signal path connected to the line to vary the delay from a basic value of .upsilon..sub.O by .+-..DELTA..UPSILON., the delay time of the control signal path is given a value which has a selected relation to .upsilon..sub.O.

Abstract: To prolong the useful life of a diamond guide element which serves to guide a transducer and which is provided with a contact surface via which the element in use bears against the surface of a record carrier while the carrier moves relative to the element, the element is constructed so that the direction of such relative movement corresponds to a high wear resistance direction of the diamond, and the contact surface thereof is periodically ground in an opposite direction in which it has a lower wear-resistance.

Abstract: A playback device for disc-shaped record carriers containing video signals stored in the grooves thereof which includes an arrangement which, in response to an applied power pulse, displaces the pickup, during playback, by a number of groove widths transversely to the direction of the groove.

Abstract: A demodulation system of a playback device for a carrier frequency signal containing both useful information in the zero passages of the signal and signal break-ins which occur in the playback device. The system includes a limiter for limiting in an asymmetrical manner a signal fed to it and a demodulator coupled to the output of the limiter. A highpass filter is connected between the limiter and the demodulator so as to couple the output signal from the limiter to the demodulator. The highpass filter substantially passes only the useful information portion of the carrier signal and suppresses any break-ins introduced into the signal.

Abstract: A method of producing a record carrier with stored signals thereon and the record made thereby. The method comprises applying to a flexible record carrier hill and dale undulations which correspond to a broadband signal in the form of a frequency modulated carrier frequency oscillation, further applying at least one further signal of lower frequency superimposed on the broadband signal, and selecting an amplitude for the further signal such that in playback of the stored signals by a skid-shaped pickup operating by compression of the hills, even the lowest hills contact the skid-shaped pickup and are compressed thereby.

Abstract: In a recording or playback system in which information is stored along a spiral track on a flexible record carrier foil which rotates at a high velocity on an air cushion above a stabilization surface, and playback is to be effected according to the pressure sensing technique, the adverse effects of static electrical charges which can be created when frictional contact occurs between the foil and points on the stabilization surface are eliminated by providing the stabilization surface with a grounded electrically conductive region in the vicinity of the path followed by a signal transducer along a radius of the foil plane as it traces the sprial track and by causing the foil to be closer to the conductive region than to the mass of the transducer.