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Telefunken Fernseh Und Rundfunk Gmbh

Ernst F Schroder

Jens Spille

Hans-Joachim Platte

Walter Voessing

Gerhard Dickopp

Jurgen Wermuth

Heinz-Werner Keesen

Otto Klank

Fritz Weisser

Dietmar Uhde

Jurgen Kaaden

Gunter Oberjatzas

Rolf Schiering

Klaus Goken

Georg Plenge

Leon Maria Van De Kerkhof

An electronic memory apparatus for a device containing a recording medium for storing information. The device cooperates with a recording or reproducing instrument when said device is disposed therein, and is controllable by a data processing and control circuit. The memory apparatus has a first, programmable memory section, which is alterable by a user of the device, for storing data pertaining to the use of the device, and a second, programmable memory section for storing data pertaining to the characterization of the information which may be recorded on said recording medium.

Memory device having multiple memory regions for a recording device

A cassette for use with a recording apparatus comprises: a housing for a recording medium, the housing having a first surface and side walls, the recording medium being accessible through one of the side walls; at least a part of a chip card affixed to the housing, forming a second surface of the housing and closing the cassette, the chip card part having a memory formed integrally therewith and externally accessible contacts; and, the contacts of the chip card being positioned on the second surface to be engageable by corresponding contacts in the recording apparatus when the cassette is inserted therein. One of the side walls has an access door for the recording medium and the second surface forms an upper wall of the housing as defined by the access door. The part of the chip card forming the second surface of the housing has a marking position at which light transmissivity can be controlled. The marking position can be rendered non transmissive to light to prevent recording.

Cassette including a recording medium for a recording apparatus

Recording device with electrical contacts

In a digital audio-signal transmission process, digital audio signals are coded in sub-bands. One or more scaling factors are determined for each sub-band. The coded signals and scaling factors are transmitted in data blocks, then decoded and reproduced at a receiver. The data block contains several types of information including a header, error processing information, a CRC (cyclic redundancy check) protection word, audio information including a bit allocation table, scaling factor selecting information, one or several scaling factors per transmitted sub-band, filler bits, and supplementary information with audio-signal-dependent supplementary information. To improve the protection of the above-described sub-band coded audio signals against transmission errors, supplementary error protection information or an error protection bit is added to the data block instead of filler bits, in order to protect the scaling factors. Acoustically uncomfortable play-back disturbances caused by scaling factor errors are thus eliminated. The invention may be used in digital audio broadcast (DAB), DAB-receivers, recorders and play-back systems.

Error protection system for a sub-band coder suitable for use in an

In a broadcast receiver, a dynamic compression of the signal is switched on or off in dependence on whether such a compression has been carried out at the transmitting end. An identification bit is transmitted for identifying this compression at the transmitter end. The object is to create a broadcast receiver which effects automatic switching-on or switching-off of an amplitude compression but manages without a transmitted identification bit. The received audio signal is applied to a signal analysing circuit which determines the scale factors of the signal and generates switching voltages dependent on the scale factors. The present invention has particular applicability for broadcast receivers in a motor vehicle or with subsequent signal recording.

Broadcast receiver

A radio broadcast receiver for receiving digitally coded sound broadcasting data (DAB) includes a bit error rate measuring device. A control device controls the reproduction of the sound broadcasting data, wherein a reception quality threshold value is defined in the control device and, upon the measured reception quality falling below the threshold value, the control device alters the reception quality and/or the reproduction signals in a perceptible manner.

Artificially reducing signal reproduction quality of received degraded

A method of recording bursts of digital data onto a rotating recording medium having a helical data track moving at a fixed linear rate with respect to a read/write unit includes the steps of temporarily storing the data bursts and reducing the data rate of the bursts during storage. The bursts are stored as clusters at spaced locations around the track while leaving pauses between the clusters. The pauses are used to relocate the read/write head to the position where the next burst will be recorded before recording the next burst.

Process for recording and/or reproducing digital data on a record carrier

In a method of transmitting a signal wherein the signal is partitioned into windows comprised of overlapping blocks with each block containing a partial signal. The partial signal in each block is converted into a digital signal and individually coded with a selected window function f(n). The overlapping areas of the window functions are weighted such that the resultant of the overlapping functions in each block equals one. The coded signals are transmitted. The received signals are reconverted into partial analog signals. The window functions are selected in accordance with frequency changes in the original signal.

Method for transmitting a signal

A method of digital transmission of an audio signal, in which in order to save transmission and/or memory capacity, the digital signal is converted, before transmission, into signals representing the short-term spectrum of time sections of the digital signal and portions of this signal are processed on the basis of psycho-acoustic laws, with portions of this signal lying below given thresholds left unconsidered, with at least one first threshold being defined below which only amplitude values outside of psycho-acoustically differentiable frequency ranges are left unconsidered.

Method of transmitting an audio signal

A system for transmitting and receiving digitalized audio signals, particularly via satellites, wherein data sequences are arranged in timely succession within frames, wherein before transmission, the digitalized audio signal is converted to a digital signal representing the momentary frequency spectrum and, during subsequent coding of the digital audio signal to be transmitted, portions of this transformed signal are given different weights on the basis of psychoacoustic laws with respect to the accuracy of their representation.

Transmission system

A circuit arrangement for generating a control voltage which is dependent upon an alternating voltage. A charging capacitor is provided which has a charge that is representative of the control voltage which can be varied by controllable charging and discharging of the capacitor. A charging circuit including a transistor is connected so that the alternating voltage is coupled to the transistor base and the transistor collector-emitter path is connected between a charging current source and the capacitor for charging the capacitor under control of the amplitude of the alternating voltage, with the collector voltage of the transistor being representative of the charge state of the capacitor. A capacitor discharge circuit is connected to provide a discharge path for the capacitor, the discharge path having a variable conductance. A capacitor discharge control unit, including a delay member is connected for increasing the conductance of the discharge path in dependence on the time elapsed after a decrease of the alternating voltage amplitude.

Circuit arrangement for generating a control voltage which is dependent

A pulse code modulated audio signal transmission system which compensates for signal interference in the pulse code modulated audio signal. The system includes a first device for receiving an audio signal and for converting the audio signal into a pulse code modulated audio signal, and a second device for receiving the audio signal and for producing an auxiliary signal corresponding to the audio signal but having a smaller bandwidth than the audio signal. A transmission circuit is connected to the first and second devices for receiving the pulse code modulated audio signal and the auxiliary signal and for producing an output signal which comprises the audio signal with portions of the audio signal which contain interference being substituted with corresponding portions of the auxiliary signal.

System for compensating signal interference in a PCM audio transmission

An electronic amplifier having a transmission factor which can be varied by means of a control voltage, specifically an expander. A switch is provided for selective operation of the amplifier with a fixed control voltage or with a variable control voltage, with this switch being coupled with circuitry for reducing, during operation of the amplifier with a fixed control voltage, the output voltage of the control circuit generating the variable control voltage.

Electronic amplifier having a transmission factor that is variable by

An electronic amplifier composed of an electronically controllable amplifier element having a control input for receiving a voltage the value of which determines the gain of the element, with one such value being a predetermined basic gain value of the amplifier element, a control voltage generating circuit for generating a control voltage whose value determines the voltage at the control input of the amplifier element, the element and circuit being constructed for causing the gain of the amplifier element to be unity for one voltage value at its control input and to be different than unity for other voltage values, a nonlinear filter unit connected between the control voltage generating circuit and the amplifier element control input for supplying to the control input a voltage determined by the control voltage, the filter unit including an integrating branch and a differentiating branch having a rectifier device for causing the differentiating branch to be effective only during periods when the control voltage is varying in a selected direction, and a device for switching the amplifier element and the control voltage generating circuit to a mode of operation in which the amplifier element operates with a constant gain value.

Electronic amplifier

The invention relates to a circuit arrangement in a compander system for generating a direct control voltage which is dependent on an alternating voltage with the circuit arrangement including a time constant switch. The conductance determining the time constant in a charging current circuit is constantly varied in the transfer range in dependence on the voltage of a charging capacitor when a time constant switch takes place from one fixed value to a second fixed value.

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Hanover, Germany

Ernst F Schroder