Ted Bildplatten Aktiengesellschaft, Aeg-telefunken, Teldec

Licentia Patent-verwaltungs Gmbh

Aeg-telefunken-teldec

Gerhard Dickopp

Ernst F Schroder

Benno Jahnel

Wolfgang Rainer

Jurgen Wermuth

Bodo Schultz

Hans-Joachim Thuy

Lothar Oertel

Paul Ludwig Dummen

Wolfgang Frey

Otto Brehm

Manfred Potter

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.

Amplifier with variable gain

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 point in the useful signal path and which applies to the control voltage generator a control signal dependent on the difference between the signals received by the combining circuit.

Signal dynamic compression and expansion circuits

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.

Amplifier with controllable transmission factor and switchable control

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.

Circuit for compensating time errors in a television signal,

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.

Method for working or reworking a diamond guide element

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.

Playback device for a disc-shaped record carrier with transducer lifting

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.

Demodulation system with dropout correction

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.

Record carrier, method of producing the record carrier and method for

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.

Growing community of inventors

Berlin, Germany

Gerhard Dickopp