Abstract: An impedance converter includes an emitter follower constructed of a first transistor with a first resistor connected between an emitter electrode of the first transistor and an output terminal. Input to the emitter follower is provided by a second transistor of complementary type, with input signal applied to the base of the second transistor and the emitter electrode of the second transistor coupled to the base of the first transistor with a second resistor. Bias current in the second transistor and second resistor is in constant proportion to bias current in the first transistor and first resistor. Output impedance can be made positive, negative or zero by appropriate proportioning of the first and second resistors.

Abstract: Items of auxiliary information are transmitted in an AM radio broadcast signal by phase angle modulating the AM carrier with digitally encoded data representing the auxiliary information. The items of auxiliary information are allocated to a cyclically recurring number of groups, each group consists of two equal length information blocks. Each information block includes an information word and a check word. Different offset words are superimposed on the respective ones of the check words. The offset words are useful for the synchronization of the information blocks in a receiver.

Abstract: A method of transmitting an analog signal including the steps of converting the analog signal into a digital signal and using windows to subdivide the digital signal into successive blocks. The blocks are evaluated for level changes, and when a level change is below a predetermined level the blocks are overlapped by 50%. The signal segments within the blocks assessed using analysis windows. The signal segments are transformed using subsampling and time domain aliasing cancellation to compensate for aliasing components. The signal segments are inverse transformed and assessed using synthesis windows. The blocks are rejoined in overlapping fashion. When the level change is above the predetermined level the signals are subdivided into blocks and the blocks are overlapped by less than 50%, or not overlapped at all. The signal segments are fully scanned, compressed and transformed. The signal segments are finally inverse transformed and expanded.

Abstract: In order to compatibly transmit teletext data in the form of special characters, fine textures and color hues at higher WST levels, complementary data in the form of one or more associated complementary pages are transmitted for each page of teletext by the broadcaster in addition to the basic teletext data of conventionally structured teletext pages (level 1). The complementary data for some or all teletext pages are transmitted preferably in at least one complementary page. In the receiver, the complementary page(s) associated with a selected teletext page are temporarily stored separately from the corresponding teletext page(s) and processed so that the characters associated with the basic data are displayed in those character positions where there is no complementary data present. The characters associated with the basic data in cooperation with the complementary data are displayed in those character positions where complementary data is present.

Abstract: A television signal processing system develops a television signal containing wide aspect ratio image information which is compatible with a standard aspect ratio television format. One image line is separated from every group of four successive image lines. The remaining image lines are vertically compressed, whereby vacant regions ("bars") appear along the top and bottom edges of a displayed image. The separated image lines are scrambled and inserted into the vacant regions. An image display including the vacant regions exhibits a standard aspect ratio, while the active image area between the vacant edge regions exhibits a wide aspect ratio.

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: Transmitting a signal wherein the signals is segmented by means of windows into successive overlapping blocks, the partial signals contained in the blocks are converted by transformation into a spectrum, with the spectra then being coded, transmitted, decoded after transmission and converted back into partial signals by retransformation. Finally, the blocks containing the partial signals are joined in an overlapping manner, with the overlapping regions of the blocks being weighted such that the resultant of the window functions in the respective overlapped regions equals one. To2.2. In order to avoid interferences in adjacent blocks upon changes in the signal amplitude, the length of the window functions is selected as a function of signal amplitude changes. The method is suitable for the treatment of audio and video signals which are subjected to data reduction during transmission.

Abstract: The invention relates to a function system and its use in image transmission. According to the invention, a vector is transformed with a matrix in such a manner that simple logic addition and linkage circuits are sufficient.

Abstract: A coil arrangement with three windings arranged coaxially, where the outer coils are connected in series. The inductances of the outer coils are of equal magnitude and their magnetic fields have opposing polarities.The center winding induces currents in the series circuit of the outer windings which cancel each other out. The outer windings with their stray inductances form a coil which is separated from the center one and can be applied for other purposes.

Abstract: For the transmission of synchronizing information for a PCM signal transmitted in biphase code, a synchronizing pattern is provided which is composed of a biphase signal that has been shifted by one-half bit period relative to the data portion of the transmitted signal.

Abstract: A magnetic tape apparatus for recording of data, including two spaced apart tape guides for guiding a movable magnetic tape therebetween, the portion of the tape between the tape guides being in tension, magnetic heads between the guides for scanning the tape, and a main tape drive which selectively moves the tape continuously in a path which includes a segment extending between the guides past the magnetic heads, the tape guides and magnetic heads being shiftable relative to each other independently of the main tape drive for longitudinally shifting the portion of the tape between the tape guides relative to the magnetic heads.

Abstract: Loudspeaker unit including a frame (FIG. 2) serving as sound guide to which the loudspeaker chassis (FIG. 1) is releasably fastened. According to the invention, form-locking cooperating detent means (4-6, 29-31) are provided on the frame and on the loudspeaker chassis. The loudspeaker chassis can be inserted into the frame by means of a relative translatory movement and can be removed by a rotational movement. Thus it becomes possible to install the loudspeaker in the frame and remove the loudspeaker from the frame by means of automatic machinery.

Abstract: A picture tube connecting device, including a common integral insulating housing, connector contacts in the common housing for electrically contacting a picture, and at least one potentiometer, including a focus adjusting potentiometer in the housing, electrically connected to the connector contacts for conducting electrical current to the picture tube via the connector contacts. A high voltage connector is provided for electrically connecting a high voltage to the focus adjusting potentiometer.

Abstract: A remote control unit, particularly for a television receiver or a video tape recorder, having a limited number of keys which have different functions that are identified by lettering presented on display elements corresponding to the keys, depending upon which appliance is selected for control. The remote control unit employs a microprocessor which cooperates with plug-in memories for the various appliances, the memories defining the key usages and corresponding lettering, etc. The remote control unit includes an additional display element for providing brief instructions to the user or displaying information received from the controlled appliance via a return channel.

Abstract: A method for transmitting digital video signals wherein spectral values are sorted according to magnitude and leading zeros are suppressed. In this way, the average word per pixel length can be reduced to about 1 bit, with image quality remaining acceptable.

Abstract: The invention concerns a coil arrangement with three windings arranged coaxially, where the outer coils are connected in series. The inductances of the outer coils are of equal magnitude and their magnetic fields have opposing polarities.The center winding induces in the series circuit of the outer windings currents which cancel each other out. The outer windings with their stray inductances form a coil which is separated from the center one and can be applied for other purposes.

Abstract: Decoder for a frequency keyed signal, particularly an FSK videotext signal. To avoid isochronous distortions, precise matching of the decoder is necessary. Due to the provision of a additional AFC circuit (11) to regulate the natural frequency of the VCO (5) in the PLL loop (3-5) of the decoder, such matching is no longer required.

Abstract: The invention concerns a phase control circuit and a special digital controlled oscillator. According to the invention the digital controlled oscillator oscillates at two frequencies which are slightly above and slightly below the input frequency.

Abstract: When recording a PCM signal, particularly an audio signal, on the oblique tracks of a magnetic tape, e.g. for example of a videorecorder, errors occur in the digital signal during the change of heads. These errors are removed in that, in the region where the scanning of the heads overlaps, phase matching of the bit clock pulses is effected, the bit patterns are matched and the number of bit clock pulses is increased or reduced before the next change of heads.

Abstract: A switched mode power supply, particularly for a television receiver with standby operation, including a protection circuit for limiting the current on the primary side of the power supply transformer and preferably also a protection circuit against too high a voltage on the secondary side of the transformer. According to the invention, a further protection circuit including a thyristor is provided on the primary side so as to periodically block the switching transistor of the power supply oscillator when the current on the primary side becomes too high and exceeds the limit value.