Abstract: To be able to scan the sprocket holes of a film with improved precision by means of a film scanner, in which a correction signal is generated for compensating picture steadiness errors, it is proposed that the light source generates light in the infrared range, and that the scanning sensor(s) is (are) sensitive in the infrared range.

Abstract: To be able to scan the sprocket holes of a film with improved precision by means of a film scanner, in which a correction signal is generated for compensating picture steadiness errors, it is proposed that the light source generates light in the infrared range, and that the scanning sensor(s) is (are) sensitive in the infrared range.

Abstract: A telecine scanner, with which the horizontal picture steadiness errors are reduced by the film guidance in the area of the film gate 5, includes a first guiding element 11 supporting one of the longitudinal edges of the film 4 at at least two points in the film gate 5 in the area of the radiation path 6. In addition, two guiding elements 12 are provided, which are spaced substantially centrically apart from the first guiding element 11 and engage the other longitudinal edge of the film 4.

Abstract: A method of correcting picture steadiness errors (or film weave correction) in telecine scanning is proposed, in which, in a first step, at least one sample area of the picture contents of the video signal obtained by film scanning is determined by way of structure recognition, this sample area corresponding to a curvature in the picture contents. In a second step, it is checked, by way of comparison, whether the determined sample areas are recognizable in a search area of the sequential frame. In a third step, motion vector signals are generated when the sample areas are recognized again in the sequential frame, these motion vector signals defining the direction of motion and the extent of deviation of the position of the determined sample area from the position of the recognized sample area. In a fourth step, parameters of a transform function are determined by the motion vector signals.

Abstract: In a film scanner for optically scanning a film for obtaining a picture signal, which film is moved at a constant speed, an image position correction which is as motion-independent as possible, is ensured in that the film scanner at least doubly scans at least parts of each film image and determines image position errors by comparing the two scanning signals of the same nominal image content, and corrects the picture signal in dependence upon the determined image position error.

Abstract: In a film scanner for optically scanning a film for obtaining a picture signal, which film is moved at a constant speed, an image position correction which is as motion-independent as possible, is ensured in that the film scanner at least doubly scans at least parts of each film image and determines image position errors by comparing the two scanning signals of the same nominal image content, and corrects the picture signal in dependence upon the determined image position error.

Abstract: Data signals recorded in oblique tracks on a magnetic tape, after they are picked up, preamplified and prefiltered, are rectified and converted to digital values representative of amplitude in respective segments distributed over track lengths. For each segment position in a track, the values are averaged and inverted by a ROM and stored in a RAM at track segment addresses. The values thus stored are converted into analog form and then used as multipliers in a multiplication stage following the preamplification and prefiltering. The output of the multiplier can readily be shaped into unambiguous data signals for further processing.

Abstract: For reliable playback of digital video signals in slow-motion operation over a wide range of slow-motion speeds, auxiliary playback heads are positioned closely behind normal playback heads and offset by half a track width therefrom. Each of the playback heads have a circuit for regenerating clock and data signals which includes a PLL circuit and all of the PLL circuits have an output for the signal that shows whether the PLL circuit is locked in or not. The lock-in signals are supplied to first address inputs of an ROM which has a principal output showing whether the normal playback heads or the auxiliary playback heads have the larger number of locked-in PLL circuits and the group of playback heads having that larger number of locked-in PLL circuits is selected for having the data and clock signal outputs passed on to playback channels for further processing. The control of the switching circuit is improved by having auxiliary outputs of the ROM fed back to second address inputs thereof.

Abstract: To the phase locked loop for controlling the oscillator that regenerates a bit-rate clock signal from a data signal by means of a phase comparison circuit followed by a low pass filter, the output of which controls the oscillator frequency, a digital frequency comparison circuit is provided for assuring that the oscillator frequency will be brought into the capture range of the phase locked loop. The output of the digital frequency comparison circuit is converted from digital to analog form for being used in combination with the low pass filter output to control the oscillator. Frequency and phase control signals are applied to opposite electrodes of a variable capacitance diode in the frequency determining circuit of the oscillator.

Abstract: When the relative speed of the head wheel to the tape transport is reduced for recording at a lower data rate, a resistance interposed between the stationary driver amplifier and the stator of a rotary transformer is reduced to produce a mismatch of the coupling between the driver amplifier and a recording amplifier on the head wheel. The latter is connected to the recording head. The mismatch lowers the upper cut-off frequency of transmission through the rotary transformer and shifts the frequency transmission band downward also lowering the lower cut-off frequency.

Abstract: 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.

Abstract: The correction of broadband signals reproduced from magnetic tape are corrected for distortion by three stages in cascade, which the first serves to correct distortion in the group propagation time through the system of playback magnetic head and playback preamplifier, the second directs for amplitude distortion including a 90.degree. phase rotation and the third stage provides equilization to compensate for high frequency losses.

Abstract: Digital color television signals intended to be recorded in serial bit form are first subjected to predistortion to compensate for nonlinear distortion digitally computed for each serial bit on the basis of the pattern established by a predetermined number of precursor bits, which requires digital to analog conversion of the multibit parallel output of the predistortion computation. The converted output is then filtered on an analog basis to compensate for linear distortion, as by emphasizing the higher frequencies. In reproduction, the similar combination of analog and digital distortion compensation is used, first filtering and then, after retrieving the bit clocking frequency and phase, analog to digital conversion and compensation for nonlinear distortion by programmed interpretation of a parallel multibit input to select correctly the bits of an output serial bit stream. The latter can be subjected to conversion into the usual eight bit parallel color television signals.

Abstract: In the transmission of a television signal containing a luminance signal between a transmitting station and a receiving station of a television system, the picture resolution at the receiving station is compatibly increased by: effecting planar prefiltering of the luminance signal at the transmitting station and a corresponding planar postfiltering of the luminance signal at the receiving station; effecting offset sampling or offset modulation of the luminance signal at the transmitting station and a corresponding sampling conversion or demodulation of the luminance signal at the receiving station; deriving an additional signal from the luminance signal for increasing picture resolution, reducing the amplitude of the additional signal at the transmitting station and transmitting the additional signal together with the original luminance signal to the receiving station; and increasing the amplitude of the additional signal at the receiving station to an extent corresponding to the reduction performed at the tr

Abstract: In the transmission of a color television signal containing chrominance burst and sync signals over a Nyquist channel between a transmitting station and a receiving station, a method for modulating and synchronously demodulating the television signal according to the offset modulation and offset sampling principle. The chrominance burst or sync pulses are used as a reference signal for frequency recovery at the receiving station. An additional reference signal is generated at the transmitting station and transmitted over the Nyquist channel. The additional reference signal is utilized for phase recovery at the receiving station.