U.S. Philips Corporation

Erich Langer

Harald E Melwisch

Friedrich Sommer

Uwe Jahnke

Helmut Mach

A recording system for recording signals on a magnetic tape uses a recording apparatus and cassettes, each cassette containing a specific length of magnetic tape, and has a timer for setting time-preprogrammed automatic recordings. A detection unit determines the maximum time available for recording on a cassette placed in the apparatus and a comparator compares an output signal of the detection unit with a reference quantity which is a measure of the total time required for the preprogrammed automatic recording(s). When this required time exceeds the maximum time available for recording with this cassette, an alarm signal is produced. The cassette has marks which are sensed by the detection unit and which indicate the length of the magnetic tape in the cassette.

Preprogrammable recording system with automatic warning of time limit

The invention relates to a recording and playback apparatus for video signals including a drive shaft for driving a record carrier, whose revolution speed can be controlled by a servo system, and a switching device to ensure that a new recording without interruption follows an existing recording, said apparatus comprising a measuring and storage device for measuring and storing the difference in phase between the pulses supplied by the tacho-generator and the pulses scanned from the synchronizaton track which device is followed by a comparator, for comparing the stored measuring value with the reference signal for the servo system, which comparator if its input signals are equal supplies its output signal to the servo system as the measuring signal. Such a servo system prevents the occurrence of undesired phase shifts at the transition from the existing recording to the new recording. The stored value, representing the phase difference between the tach signal and the recorded vertical sync signal, controls the delay of the tach signals when a new video insert is added.

Recording and playback apparatus for video tape editing

In a recording and playback apparatus the tachometer of the servo system for controlling the speed of the drive shaft uses a disc with a closed magnetizable track, which cooperates with an even number of equidistantly spaced magnetic heads connected to a direct voltage source in the playback mode. Each head successively magnetizes the track in an opposite sense. One of the heads scans the magnetizations stored in the track for supplying the input signal for the servo system during a recording. When a new recording is made which is to follow an existing recording, the magnetic heads are disconnected from the direct voltage source, and switching from the playback to the recording mode is effected by means of a switching device which can be controlled by the pulses scanned from a synchronization track on the record carrier.

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Vienna, Austria

Erich Langer