Abstract: A radio-frequency (RF) receiver generally contains an RF amplifier, a mixer stage, a mixer oscillator, a demodulator and an AGC (automatic gain control) circuit, to which the output voltage of the demodulator and a set voltage value for the automatic gain control are applied. Such RF receivers have a non-optimal signal-to-noise ratio under certain circumstances. The present invention improves the signal-to-noise ratio in such high frequency receivers, as well as the effectiveness of the AFT (automatic fine tuning) circuit. The amplitude of the AGC set voltage value is regulated depending on the frequency of the received RF signal so that the mixer stage is optimally controlled at all frequencies of the RF signal. In one embodiment, a PLL circuit connected to the output of the intermediate frequency amplifier to regenerate the non-modulated image carrier, is further used to ensure automatic fine tuning by regulating the frequency of the mixer oscillator.

Abstract: A rack drive contains a suspension tooth element which is formed by a rack which has a guide opening parallel to its row of teeth. The rack opening is guided on a bearing bolt of the drive pinion for the rack. The suspension tooth element is preferably connected via a drive pin to a device which can be variably positioned and is produced integrally from an acetyl polymer. The rack drive can advantageously be used as a positioning device for controlling a scanning and/or recording device in a recording and/or playback unit for optical recording media but is not limited to such.

Abstract: A magneto optical disc system includes a disc having permanently recorded tracks overlain with magneto optical recording material. Data is recorded in the magneto optical material in tracks superimposed over the permanently recorded tracks, using the read-only data to define magneto optical tracks. The magneto optically recorded data is correlated with the prerecorded data for defining the location of data stored in the magneto-optic tracks.

Abstract: A disc playback system monitors coded information in the tracks of discs being played back in order to determine the radial position of the information pickup apparatus. Responsive to a disc stop command, the radial position is utilized to determine the angular speed of the disc, and thereby the speed of the motor that is rotating the disc. A time period, necessary for a predetermined signal which accelerates the motor in the reverse direction to stop the rotation of the disc, is calculated in response to the angular speed at the time the stop command is instituted. Thereafter the predetermined reversing signal is applied to the motor for the calculated period to stop the rotation of the disc.

Abstract: A method of simultaneously transmitting and decoding an audio signal and an auxiliary signal which is inseparable from the audio signal includes the step of allocating a loudness level to the audio signal which is higher than the level of the auxiliary signal whereby the auxiliary signal is inaudible during playback of the audio signal and does not deteriorate the playback of the audio signal. The audio signal is encoded by dividing it into a number of frequency bands. The auxiliary signal is transmitted in one of the frequency bands at a level much lower than the level of the audio signal.

Abstract: Electrical contact surfaces, especially when connected to a chip, are designed to be purely functional. However, according to the present disclosure, the contact surfaces are designed so that their external shape is that of a visible letter or symbol with a meaningful content. These contact surfaces may, e.g., be placed on cassette casings for recognition. In a stripe or bar code unit consisting of several code components, i.e., bars, individual bars are electrically conductive to facilitate additional coding. The electrically conductive bars or the contact surfaces are preferably connected to the terminals of an integrated circuit.

Abstract: 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.

Abstract: An integrated circuit achieves a burst mode standby operation for a switched-mode power supply by driving a switching transistor. One winding of a transformer is connected to inputs of two differently biased rectifier circuits and the sum of the output voltages of these circuits is applied to a control terminal of the integrated circuit.

Abstract: A filter circuit having an amplifier stage, an upstream filter and a downstream bandpass filter. The filter includes, inter alia, a rejection circuit tuned to an intermediate frequency and a series circuit, tuned to an image frequency and formed by a capacitor and a .lambda./4 coaxial stub. The inductance formed by the coaxial stub is shared by the series circuit and the rejection circuit.

Abstract: In known processes for controlling a receiver-side appliance, data concerning the identification signal of a program being received are derived automatically from the identification signal transmitted together with the program. The aim of the invention is to allow a program received after the program currently being received to be programmed in a receiver-side appliance without having to input manually individual essential data of the identification signal. According to the present invention, a first identification signal received when a receiver-side control device is activated and a predetermined number of subsequent, different identification signals are counted together and stored automatically in the data contained in the identification signals concerning the identification signal received when the predetermined number is reached and/or the previously received identification signal and the first identification signal.

Abstract: A process for reducing the friction between a rotating head drum and a tape-shaped recording medium which surrounds the head drum for recording and/or playing back information. In order to shorten access time to information stored on the tape-shaped recording medium, some recorders have the recording medium mounted in a cassette which remains threaded even during rewinding, and surrounds the head drum in the same way as in the play and search modes. Because the tape remains threaded during rewinding, such recorders, also called full-loading recorders, suffer from increased friction between the rotating head drum and the tape moving in the reverse direction. To reduce friction, the speed of rotation of the head drum is increased by a factor, preferably a factor of 2, during rewinding.

Abstract: The secondary winding is connected, via the series circuit of a capacitor and a second diode, to the charging capacitor which delivers the operating voltage. The centre point of the series circuit is connected to earth via a third diode. This enables energy to be recovered, in that the energy stored in the capacitor is delivered back to the charging capacitor during the inhibiting phase of the switching transistor.

Abstract: 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.

Abstract: A method and apparatus for setting the parameters of an equalizer. Equalizers are used for equalizing distorted signals. However, optimum equalization is only achieved when the parameters of the equalizer are optimally set. To set the parameters of an equalizer optimally, the output signal of the equalizer is rectified in a full-wave rectifier. The output signal of the latter is integrated in an integrator. The parameters of the equalizer are set by a microprocessor according to an algorithm. In one embodiment, when the integration time is predetermined, the parameters of the equalizer is changed until the level of the integrated signal becomes a maximum. In another embodiment, when the maximum level of the integrated signal is predetermined, the parameters of the equalizer are changed until the integration time becomes a minimum.

Abstract: Apparatus requiring a plurality of control signals is provided with a fuzzy logic controller. The fuzzy logic controller is programmed with a plurality of control functions. Respective parameters determinative of the control signals are applied to the fuzzy controller in time division multiplex fashion, and concurrently respective control signals provided by the fuzzy controller are time division multiplex applied to respective control signal paths.

Abstract: Switch mode power supplies produce a brief pulse-like load on the mains and have a high harmonic content. Such a high harmonic load on the mains is undesirable. There are increasingly strict regulations for the level of harmonic loads connected to the mains. The present switch mode power supply includes a series circuit formed by an inductor and a diode connected between a charge capacitor, which is dimensioned to be relatively small, and a pickoff of a primary winding of a transformer of the switch mode power supply. A relatively large energy storage capacitor connected to the primary winding is decoupled from the charge capacitor by a second diode. The series circuit produces an additional charging current, which extends the current which is drawn from the mains during one half cycle of the mains voltage, and reduces the amplitude of the current.

Abstract: The present infra-red remote control transmitter understands external formats, and those with toggle-bits and different carrier frequency ranges, and transmits signals in these data formats to the appropriate devices, with or without a toggle-bit. The remote control receives and transmits infra-red formats and comprises an infra-red receiver with a microprocessor and/or with two carrier frequency oscillators to generate two modulation frequencies, in which case it is provided with two infra-red receivers. An externally formatted data word with toggle-bits is subjected, after being read at least twice, to a comparison inside the microprocessor, from which the presence of toggle-bits, their number, position and the carrier frequency of the data word are found.

Abstract: An actuating device for a pinch roller in a tape recording and/or playing device has a capstan spindle driven by a mechanism supported on a chassis. A pinch lever supports the pinch roller. At least one drive lever is rotatably coupled to the pinch lever and mounted to pivot about a fixed axis normal to the chassis for swiveling the pinch roller between resting and working positions. A spring connects the pinch lever and the at least one drive lever for urging the pinch roller against the capstan spindle only in the working position. A first guide controls the swiveling of the at least one drive lever. A lift roller is rotatably supported by the pinch lever and disposed in proximity to the pinch roller. The lift roller has a cylindrical region and a conical region having a diameter which increases in a direction away from the chassis.

Abstract: In a switch mode power supply which includes a transformer for DC isolation and a switching transistor, a control transistor which controls the switching transistor is switched on by an appropriate control voltage during the isolating phase until the collector voltage of the switching transistor has fallen to a minimum. The control transistor is preferably switched on during the isolating discharge time and the subsequent oscillation phase of the transformer.

Abstract: A time coding system of high resolution for a digital audio and video recording system is disclosed. Various methods of structuring: time code for recording are disclosed which enable time code reading at high tape transport speeds to facilitate automatic search/forward and reverse. A time and control code generator for video recording and replay use comprises a pulse generator generating a pulse having a television frame frequency repetition rate. A source of a time code signal is related to the television frame frequency, and comprises data bits representing hours minutes seconds and frames. A pulse position modulation means is coupled to the pulse and in response to the data its representing hours minutes seconds, modulates a trailing edge of the pulse to a first position responsive to the data bits having a logical 1 value and modulates the trailing edge to a second position responsive to the data bits having a logical 0 value.