U.S. Philips Corporation

Dietfried Susz

Harald E Melwisch

Harro Kormann

A circuit arrangement for generating an actuating voltage for a piezo-electric element (1) of a positioning device intended for positioning a recording and/or reproducing head relative to an information track. A control signal whose amplitude is representative of a positional error is applied to a signal conversion stage (7) in the form of an amplitude modulator. The modulator output signal is applied to the primary (10) of a transformer (11). The piezo-electric element is connected to the secondary (12) via a bipolar switching device (13) which is actuated by a periodic pulse-shaped switching signal which, by means of a pulse-shaper stage (20), is derived from a carrier signal supplied by an oscillator (18). The switching signal corresponds in time to only one of the two peak amplitude values of the carrier signal and has a pulse width less than half the period of the carrier signal.

Circuit arrangement for generating an actuating signal for a

A reproducing apparatus for television signals recorded on a magnetizable record carrier in the form of a tape comprises a rotatable transducer arrangement which for reading television signals which are recorded in adjacent oblique tracks which extend parallel to each other carries two magnetic heads of mutually different azimuth angles, whose azimuth angles correspond to the azimuth angles of the magnetic heads used during recording. In such an apparatus steps have been taken to ensure that during a mode of operation with stationary record carrier or with a record carrier speed deviating from the normal speed each of the two magnetic heads reads a track in which the television signals have been recorded with a magnetic head having the same azimuth angle as the magnetic head reading it. Furthermore, the signal path for the television signals being reproduced includes a delay device for said signals, which shifts the television signals corresponding to the consecutive fields in such a time relationship to each other that, without a phase jump between the horizontal synchronizing pulse trains of consecutive fields, the differences in the time intervals between every two consecutive vertical synchronizing pulses of each field are zero or a minimum respectively.

Video reproducing apparatus with variable delay means

Circuit arrangement for processing a NTSC chrominance signal in which the NTSC color synchronizing signal is modulated in phase so that PAL demodulation techniques may be used for obtaining a low-noise amplification control voltage and/or a low-noise color killing voltage.

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Vienna, Austria

Dietfried Susz