Robert Boschgmbh

U.S. Philips Corporation

Bts Broadcast Television Systems Gmbh

Axel Schulz

Josef Sochor

Berthold Eiberger

Manfred Hescher

Werner Staude

A system for non-linearly editing video and audio information, uses a device for recognizing speech in the audio information and for generating a character sequence, particularly an ASCII character sequence, to produce an edit decision list (EDL). The generated character sequence is displayed on the display screen of an indicator. With reference to marked parts of the character sequence displayed on the display screen of the indicator, editing data is derived for the EDL.

System for editing digital video and audio information

A distorted signal available at the output of a preamplifier which are derived from a magnetically recorded digital signal is differentiated twice. The second derivative signal obtained by that double differentiation is used to derive one set of pulses corresponding to both positive and negative peaks of the twice differented signal, which are then used to clock a D-flipflop. Another set of pulses is derived from the double differentiated signal responding to peaks of only one polarity thereof and these are applied to the D input of the flipflop. The output of the flipflop is a reconstituted replica of the digital signal that was originally recorded.

System for processing signals reproduced from a digital magnetic record

In order to provide a magnetic recording head with a broadband signal with minimum distortion from the reactances of wire connections and the like, a voltage controlled current source is used to feed equivalent circuits representing a magnetic head like the recording head in an output that is taken from that current source at a point that reflects the effect of the equivalent circuit to operate the controlled voltage source for providing the driving current for the recording head. Instead of a parallel coil and resistor combination in series with another resistor, the equivalent circuit can consist of another magnetic head of the same kind as the recording magnetic head but not used for recording. In practice differential or complementary cascode amplifiers are used for the voltage controlled current source at the signal input and differential or complementary final stage amplifiers are used for driving the recording head through a rotary transformer or broadband recording on tape. When the equivalent circuit is another magnetic head not used for recording, it may be convenient to drive it through a transformer, particularly when the controlled current source for which it provides a load is a differential amplifier.

Method and circuit for recording broadband signals on a magnetic record

To effectively eliminate cross-talk between the weak signals picked up by a tape transducer pick-up head with signals being applied to a recording head, a disk-like headwheel carrier has a disk-like headwheel secured thereto. The disk-like headwheel carrier is formed with a recess which defines a chamber (6) in which the preamplifier for the reproduced signals is placed. Transducer leads are passsed in a channel duct formed between the headwheel carrier and the disk-like headwheel, which is in plate form. Preferably, both the disk-like headwheel as well as the carrier are made of lightweight metal, such as aluminum, so that the reproducing amplifier is totally shielded. The recording amplifier can be placed on top of the disk-like headwheel, separated and shielded from the reproducing preamplifier.

Rotary magnetic tape transducer headwheel structure

For every playback head (6) on the head wheel (1) a sector (5) of the head wheel disk carries a preamplifier consisting of two amplifier branches operating in phase opposition, each having an input transistor stage of the grounded emitter configuration and an output transistor stage of the grounded collector configuration (sometimes referred to as an emitter follower). Both stages have voltage negative feedback. The outputs of the amplifying branches are respectively connected to opposite ends of a rotary primary coil of a multiple transformer serving to couple the rotating preamplifier circuits to stationary outputs. Blocking capacitors prevent the flow of equalizing currents in the event of any deviations from electrical symmetry. The circuit is usable for playback of recordings in the form of digital signals picked up at a rate of 2 megabits per second.

Playback preamplifier for magnetic tape recordings

The digital signal values of adjacent picture points of pairs of points straddling the picture point currently being processed in every direction are compared in terms of only their more significant bits to determine which, if any, of the pairs involve a difference of value greater than a predetermined threshold. The determination that such a value difference is present is treated as the recognition of a picture contrast feature and causes, through operation of a read-only memory, the exclusion of such a picture point pair from the averaging process for producing a substitute value for the picture point currently under processing when the latter is found unusable by means of an error-detector. The resulting system for concealing errors detected in television picture avoids disturbing the outlines of picture features as other systems do which substitute averages of neighboring picture points for picture points found to be erroneous.

Method and apparatus for concealing errors in a digital television signal

Picture points represented by a digital signal that is found to be in error are set to zero (black) value. Incoming 8-bit signals are twice delayed by one line delays, and 8-bit shift registers are provided for the undelayed, once delayed and twice delayed signals, each shift register providing three places for successive picture points. Averages are continuously formed horizontally, vertically and on both diagonals about every picture point, and when one value which is averaged is faulty, the divider at the output of the addition stage has its divisor changed from 2 to 1. The averages themselves are averaged to eliminate averages that are unusable because both inputs are faulty. The color television signal must be separately coded for the color and luminance information, and essentially the same scheme may be used for covering over errors in the color information as in the luminance information.

Method and apparatus approximately correcting errors in a digital video

The digital signals representing successive picture points of a digital television video signal is caused to pass through, in succession, two delay circuits each providing a delay of one television line interval. This makes three places available where shift registers may be connected for stepping the digital signals at picture point intervals, so that a two-dimensional array of neighboring picture points located on adjacent portions of three television lines can be made simultaneously available for correcting the signal of the central picture point if it is found to be defective. A defective picture point is caused to be represented by a null value of digital signals by an error-correcting circuit. Thus, at the same places where the video signal shift registers are connected, gates for detecting null signals may be connected, each of which is followed by one-bit shift registers for addressing a read-only memory for controlling the choice of digital signal pairs from the picture point array which will be averaged in an averaging circuit to provide the output signal. If the digital signal of the central point of the picture point array is not defective, duplicates of this signal are provided to the averaging circuit under control of the read-only memory so that the original signal will proceed to the output of the circuit. If this signal is defective, however, the read-only memory selects a pair of signals corresponding to picture points bracketing the central point to provide the average signal, in accordance with a program that takes account of which points in the picture point array are defective. If no bracketing pair of points provides nondefective signals, the memory causes a medium gray signal to be substituted for the defective center point signal. This system has the advantage that the same stages are used and the same operating times occur in the processing of every picture point, whether the signal for that point is defective or not.

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Bickenbach, Germany

Axel Schulz